# Trying to chart high/low temp

**URL:** <https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775>\
**Category:** Dashboard\
**Created:** [25 November 2025 18:43 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775 "2025-11-25T18:43:01Z")\
**Posts on this page:** 20\
**Page:** 2

<div class="post-metadata">

**Author:** ![Inq](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Inq](https://discourse.nodered.org/u/Inq)\
**Post date:** [1 December 2025 15:50 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/21 "2025-12-01T15:50:53Z")

</div>

I’m real new to Node-Red. People here have been so kind to help me out, so I thought I’d try to help others. I didn’t see where someone showed a reset capability. Here is the solution I use that resets every day.

```flows
[
    {
        "id": "b079c63558100c2d",
        "type": "mqtt in",
        "z": "660480f6a68e2c2d",
        "name": "Temperature",
        "topic": "Outside/temperature",
        "qos": "2",
        "datatype": "auto-detect",
        "broker": "b8758158381423f0",
        "nl": false,
        "rap": true,
        "rh": 0,
        "inputs": 0,
        "x": 110,
        "y": 100,
        "wires": [
            [
                "1cab0dd86162fd95"
            ]
        ]
    },
    {
        "id": "1cab0dd86162fd95",
        "type": "function",
        "z": "660480f6a68e2c2d",
        "name": "function 1",
        "func": "let old = context.get('Day');\nlet day = new Date().getDay();\nif (old != day)\n{\n context.set('Day', day);\n msg.min = 10E6;\n msg.max = -10E6;\n}\nelse\n{\n msg.min = context.get('Min');\n msg.max = context.get('Max');\n}\n\nif (msg.payload < msg.min) \n{\n msg.min = msg.payload;\n context.set('Min', msg.min);\n}\nif (msg.payload > msg.max) \n{\n msg.max = msg.payload;\n context.set('Max', msg.max);\n}\nreturn msg;",
        "outputs": 1,
        "timeout": 0,
        "noerr": 0,
        "initialize": "if (context.get(\"Day\") === undefined)\n context.set(\"Day\", -1);\nif (context.get(\"Min\") === undefined)\n context.set(\"Min\", 10E6);\nif (context.get(\"Max\") === undefined)\n context.set(\"Max\", -10E6);",
        "finalize": "",
        "libs": [],
        "x": 280,
        "y": 100,
        "wires": [
            [
                "f03eada3305694ef",
                "3155dd6e832f91d2"
            ]
        ]
    },
    {
        "id": "f03eada3305694ef",
        "type": "ui_text",
        "z": "660480f6a68e2c2d",
        "group": "e8d1ae835631bb1a",
        "order": 0,
        "width": 0,
        "height": 0,
        "name": "",
        "label": "Today's Min",
        "format": "{{msg.min}}",
        "layout": "row-spread",
        "className": "",
        "style": false,
        "font": "",
        "fontSize": 16,
        "color": "#000000",
        "x": 470,
        "y": 60,
        "wires": []
    },
    {
        "id": "3155dd6e832f91d2",
        "type": "ui_text",
        "z": "660480f6a68e2c2d",
        "group": "e8d1ae835631bb1a",
        "order": 1,
        "width": 0,
        "height": 0,
        "name": "",
        "label": "Today's Max",
        "format": "{{msg.max}}",
        "layout": "row-spread",
        "className": "",
        "style": false,
        "font": "",
        "fontSize": 16,
        "color": "#000000",
        "x": 470,
        "y": 140,
        "wires": []
    },
    {
        "id": "b8758158381423f0",
        "type": "mqtt-broker",
        "name": "Local Broker",
        "broker": "localhost",
        "port": 1883,
        "clientid": "",
        "autoConnect": true,
        "usetls": false,
        "protocolVersion": 4,
        "keepalive": 60,
        "cleansession": true,
        "autoUnsubscribe": true,
        "birthTopic": "",
        "birthQos": "0",
        "birthRetain": "false",
        "birthPayload": "",
        "birthMsg": {},
        "closeTopic": "",
        "closeQos": "0",
        "closeRetain": "false",
        "closePayload": "",
        "closeMsg": {},
        "willTopic": "",
        "willQos": "0",
        "willRetain": "false",
        "willPayload": "",
        "willMsg": {},
        "userProps": "",
        "sessionExpiry": ""
    },
    {
        "id": "e8d1ae835631bb1a",
        "type": "ui_group",
        "name": "Group 1",
        "tab": "b9feac347f4789ce",
        "order": 1,
        "disp": true,
        "width": 6
    },
    {
        "id": "b9feac347f4789ce",
        "type": "ui_tab",
        "name": "Tab 12",
        "icon": "dashboard",
        "order": 12
    }
]

```

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 19:26 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/22 "2025-12-01T19:26:01Z")

</div>

That was a nice trick you did for the new day detection.

👍

Sorry I didn't expand on that part.

Glad it is working.

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [1 December 2025 20:25 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/23 "2025-12-01T20:25:13Z")

</div>

hi i added bar-chart-data-2 min for one and max for the other after the function node , seems to be working not sure how, I haven't the foggiest

```auto
[
    {
        "id": "b3a8374aa5da37ac",
        "type": "tab",
        "label": "Flow 1",
        "disabled": false,
        "info": "",
        "env": []
    },
    {
        "id": "8449a5141f0fa835",
        "type": "function",
        "z": "b3a8374aa5da37ac",
        "name": "function 1",
        "func": "if (msg.topic == \"NEWDAY\") {\n // You need to reset values\n // you need to add stuff here.\n context.set('previous_max', 0)\n context.set('previous_min', 100)\n return // exit.\n}\n\nlet previous_max = context.get('previous_max') || 0\nlet previous_min = context.get('previous_min') || 100\n\n// get the temperature.\nconst temperature = msg.payload\n\n if(temperature > previous_max)\n{\n //\n context.set('previous_max', temperature)\n msg.topic = 'maximum'\n return msg\n}\n\nif (temperature < previous_min) {\n //\n context.set('previous_min', temperature)\n msg.topic = 'minimum'\n return msg\n}",
        "outputs": 1,
        "timeout": 0,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 280,
        "y": 160,
        "wires": [
            [
                "6769276dd1369687",
                "96f552e00a05af0a",
                "e87bd04eade7bcaa"
            ]
        ]
    },
    {
        "id": "03a0ef28daf000f2",
        "type": "mqtt in",
        "z": "b3a8374aa5da37ac",
        "name": "outside",
        "topic": "zone0/text",
        "qos": "2",
        "datatype": "auto-detect",
        "broker": "dc0340c9643bd396",
        "nl": false,
        "rap": true,
        "rh": 0,
        "inputs": 0,
        "x": 130,
        "y": 160,
        "wires": [
            [
                "8449a5141f0fa835"
            ]
        ]
    },
    {
        "id": "6769276dd1369687",
        "type": "bar-chart-data2",
        "z": "b3a8374aa5da37ac",
        "name": "bar-chart-data2",
        "x_interval": "days",
        "x_size": 24,
        "unit": "",
        "precision": 2,
        "is_meter_reading": "False",
        "agg_by": "min",
        "x": 410,
        "y": 280,
        "wires": [
            [
                "42d05518f43a7dec"
            ]
        ]
    },
    {
        "id": "42d05518f43a7dec",
        "type": "ui_chart",
        "z": "b3a8374aa5da37ac",
        "name": "",
        "group": "b5f7f90a2f77ea3d",
        "order": 5,
        "width": "18",
        "height": "4",
        "label": "newest chart",
        "chartType": "bar",
        "legend": "false",
        "xformat": "HH:mm:ss",
        "interpolate": "linear",
        "nodata": "",
        "dot": false,
        "ymin": "",
        "ymax": "",
        "removeOlder": 1,
        "removeOlderPoints": "",
        "removeOlderUnit": "3600",
        "cutout": 0,
        "useOneColor": false,
        "useUTC": false,
        "colors": [
            "#1f77b4",
            "#aec7e8",
            "#ff7f0e",
            "#2ca02c",
            "#98df8a",
            "#d62728",
            "#ff9896",
            "#9467bd",
            "#c5b0d5"
        ],
        "outputs": 1,
        "useDifferentColor": false,
        "className": "",
        "x": 610,
        "y": 280,
        "wires": [
            []
        ]
    },
    {
        "id": "96f552e00a05af0a",
        "type": "bar-chart-data2",
        "z": "b3a8374aa5da37ac",
        "name": "bar-chart-data2",
        "x_interval": "days",
        "x_size": 24,
        "unit": "",
        "precision": 2,
        "is_meter_reading": "False",
        "agg_by": "max",
        "x": 400,
        "y": 340,
        "wires": [
            [
                "42d05518f43a7dec"
            ]
        ]
    },
    {
        "id": "12efdbbefe6130e1",
        "type": "inject",
        "z": "b3a8374aa5da37ac",
        "name": "",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "0",
        "payloadType": "str",
        "x": 480,
        "y": 420,
        "wires": [
            [
                "42d05518f43a7dec"
            ]
        ]
    },
    {
        "id": "e87bd04eade7bcaa",
        "type": "debug",
        "z": "b3a8374aa5da37ac",
        "name": "debug 4",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 450,
        "y": 160,
        "wires": []
    },
    {
        "id": "dc0340c9643bd396",
        "type": "mqtt-broker",
        "name": "",
        "broker": "192.168.0.107",
        "port": "1883",
        "clientid": "",
        "autoConnect": true,
        "usetls": false,
        "protocolVersion": "4",
        "keepalive": "60",
        "cleansession": true,
        "autoUnsubscribe": true,
        "birthTopic": "",
        "birthQos": "0",
        "birthPayload": "",
        "birthMsg": {},
        "closeTopic": "",
        "closeQos": "0",
        "closePayload": "",
        "closeMsg": {},
        "willTopic": "",
        "willQos": "0",
        "willPayload": "",
        "willMsg": {},
        "userProps": "",
        "sessionExpiry": ""
    },
    {
        "id": "b5f7f90a2f77ea3d",
        "type": "ui_group",
        "name": "Group 1",
        "tab": "eaa84631f407bcd4",
        "order": 1,
        "disp": true,
        "width": "18",
        "collapse": false,
        "className": ""
    },
    {
        "id": "eaa84631f407bcd4",
        "type": "ui_tab",
        "name": "daily temperatures",
        "icon": "dashboard",
        "order": 5,
        "disabled": false,
        "hidden": false
    },
    {
        "id": "5881260ad5e9384c",
        "type": "global-config",
        "env": [],
        "modules": {
            "node-red-contrib-dashboard-bar-chart-data2": "0.9.101",
            "node-red-dashboard": "3.6.6"
        }
    }
]
![image|690x152](upload://agwPg7e3KHGx4gs8XX1WnKX0BX4.png)

```

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/0/c0eeb546716abbafc1338ceeb0f76a12ce01f0aa.png)

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/6/2/621094388a82bcd21862475a7036bef7df4379a5.png)

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 20:28 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/24 "2025-12-01T20:28:14Z")

</div>

As each message for max and min have different `topics` when they get to the `chart` node they are shown as different sets of data/lines/(what ever)

Yes, injecting a `0` will wipe the chart.  
I also believe if you send an empty payload. `msg.payload = {}` will also work from what I remember.

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [1 December 2025 20:29 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/25 "2025-12-01T20:29:53Z")

</div>

thanks  
martin

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 20:31 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/26 "2025-12-01T20:31:32Z")

</div>

(Could you post the code in the `function` node?)  
I'll show you a trick of which I've just thought to maybe help you.

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [1 December 2025 20:34 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/27 "2025-12-01T20:34:35Z")

</div>

```auto
if (msg.topic == "NEWDAY") {
    // You need to reset values
    // you need to add stuff here.
    context.set('previous_max', 0)
    context.set('previous_min', 100)
    return // exit.
}

let previous_max = context.get('previous_max') || 0
let previous_min = context.get('previous_min') || 100

// get the temperature.
const temperature = msg.payload

    if(temperature > previous_max)
{
    //
    context.set('previous_max', temperature)
    msg.topic = 'maximum'
    return msg
}

if (temperature < previous_min) {
    //
    context.set('previous_min', temperature)
    msg.topic = 'minimum'
    return msg
}

```

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 20:37 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/28 "2025-12-01T20:37:42Z")

</div>

I meant the `function` node you are using. That looks like the code I posted.  
🤷

Don't worry. Dug it up.  
Hang on while I look at it.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 20:52 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/30 "2025-12-01T20:52:58Z")

</div>

This code:

```auto
let old = context.get('Day');
let day = new Date().getDay();
if (old != day)
{
    context.set('Day', day);
    msg.min = 10E6;
    msg.max = -10E6;
}
else
{
    msg.min = context.get('Min');
    msg.max = context.get('Max');
}

if (msg.payload < msg.min) 
{
    msg.min = msg.payload;
    context.set('Min', msg.min);
}
if (msg.payload > msg.max) 
{
    msg.max = msg.payload;
    context.set('Max', msg.max);
}
return msg;

```

As I see it, it isn't the best.  
(Not a problem, but a few things I'm seeing.)

1 - ok, you got around the `new day` bit but then what you do is a problem.  
2 - when the code detects it is a new day, it needs to save the `reset` values to context. Not really the `msg.min` and `msg.max` values.

Each new day the chart/values will be thrown to their extremes.  
I'm not sure that is what you want.  
Rather to reset the stuff shown/displayed.

```auto
if (old != day)
{
    context.set('Day', day);
    msg.min = 10E6;
    msg.max = -10E6;
}

```

_Works_ but maybe this would be better.  
(I haven't tested it.)

```auto
if (old != day)
{
    context.set('Day', day);
    context.set('Min',10E6)
    context.set('Max',-10E6)
    msg.min = {}
    msg.max = {}
    return msg
}

```

This way, the context values will be set to their extremes - ready for the new day's data.  
Also a message with `msg.max` and `msg.min` will be sent with `{}` as the content.  
(You could change that to `0` as per you `inject` node to clear things. I just think this way is nicer.)

For the sake of making it easier for testing, try this code:

```auto
let old = context.get('Day');
let day = new Date().getDay();

//----
// test block here
if (msg.payload == 'TEST')
{
    context.set('Day', day);
    context.set('Min',10E6)
    context.set('Max',-10E6)
    msg.min = [] // edited
    msg.max = [] //edited (Sorry)
    return msg
}
// end test block

if (old != day)
{
    context.set('Day', day);
    context.set('Min',10E6)
    context.set('Max',-10E6)
    msg.min = [] // edited
    msg.max = [] // edited
    return msg
}else
{
    msg.min = context.get('Min');
    msg.max = context.get('Max');
}

if (msg.payload < msg.min) 
{
    msg.min = msg.payload;
    context.set('Min', msg.min);
}
if (msg.payload > msg.max) 
{
    msg.max = msg.payload;
    context.set('Max', msg.max);
}
return msg;

```

Add am `inject` node that has the payload set to `TEST` and connect it to the input of the `function` node.

Then if/when you press it, it will _WIPE_ things as if a new day.

See if that way is better.

If you like it, use it.

Delete the `inject`node and the small bit of extra code.

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [1 December 2025 20:58 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/31 "2025-12-01T20:58:20Z")

</div>

To clear the chart send an empty array `[]`

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 20:58 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/32 "2025-12-01T20:58:53Z")

</div>

Thanks.

I sometimes get those two mixed up.

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [1 December 2025 21:09 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/33 "2025-12-01T21:09:20Z")

</div>

using the inject node is not working for some reason,

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/2/4/24a0f95458bdb5f83fd7cd40f07e98cc6094c593.png)

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 21:17 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/34 "2025-12-01T21:17:54Z")

</div>

You need to put TEST in the payload field.

 ![Screenshot from 2025-12-02 08-18-28](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/d/0d67865ff5c1691b0c880d781ed9218fac57f95e.png)

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [1 December 2025 21:19 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/35 "2025-12-01T21:19:19Z")

</div>

thanks I'll see how it goes  
martin

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [1 December 2025 21:29 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/36 "2025-12-01T21:29:46Z")

</div>

Is that code any _better_?

Can you see/understand what I did and why?

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [4 December 2025 23:00 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/37 "2025-12-04T23:00:10Z")

</div>

hi i can see what you've not sure i understand it ,  
i only seem to be getting one reading (low) on a few i think ,

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/e/aebdde9336dd0926b000d97e9a24a9977d15e92e.png)

however i have found a way to get what i need using 2 charts .

```auto
[
    {
        "id": "d3637ed3c66aa0d7",
        "type": "tab",
        "label": "daily temps",
        "disabled": false,
        "info": "",
        "env": []
    },
    {
        "id": "558a976d1540e55c",
        "type": "group",
        "z": "d3637ed3c66aa0d7",
        "style": {
            "stroke": "#999999",
            "stroke-opacity": "1",
            "fill": "none",
            "fill-opacity": "1",
            "label": true,
            "label-position": "nw",
            "color": "#a4a4a4"
        },
        "nodes": [
            "e1cc8e5dcfa599e4",
            "8dc4a744a869b740",
            "6a492259f74bde19",
            "9e7148d9a5fcbfae",
            "b6ed25afa97b9f26",
            "5ae30d57abb32fac",
            "5269df838f656cd0",
            "6eaf9754b1bf4d38"
        ],
        "x": 14,
        "y": 159,
        "w": 712,
        "h": 222
    },
    {
        "id": "e1cc8e5dcfa599e4",
        "type": "mqtt in",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "outside",
        "topic": "zone0/text",
        "qos": "2",
        "datatype": "auto-detect",
        "broker": "dc0340c9643bd396",
        "nl": false,
        "rap": true,
        "rh": 0,
        "inputs": 0,
        "x": 90,
        "y": 240,
        "wires": [
            [
                "5269df838f656cd0",
                "5ae30d57abb32fac",
                "6eaf9754b1bf4d38"
            ]
        ]
    },
    {
        "id": "8dc4a744a869b740",
        "type": "bar-chart-data2",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "bar-chart-data2",
        "x_interval": "days",
        "x_size": 24,
        "unit": "c",
        "precision": 2,
        "is_meter_reading": "False",
        "agg_by": "min",
        "x": 420,
        "y": 200,
        "wires": [
            [
                "6a492259f74bde19"
            ]
        ]
    },
    {
        "id": "6a492259f74bde19",
        "type": "ui_chart",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "",
        "group": "b5f7f90a2f77ea3d",
        "order": 2,
        "width": 18,
        "height": 5,
        "label": "lowest outside",
        "chartType": "bar",
        "legend": "true",
        "xformat": "HH:mm:ss",
        "interpolate": "linear",
        "nodata": "",
        "dot": false,
        "ymin": "",
        "ymax": "",
        "removeOlder": 1,
        "removeOlderPoints": "",
        "removeOlderUnit": "3600",
        "cutout": 0,
        "useOneColor": false,
        "useUTC": false,
        "colors": [
            "#1f77b4",
            "#aec7e8",
            "#ff7f0e",
            "#2ca02c",
            "#98df8a",
            "#d62728",
            "#ff9896",
            "#9467bd",
            "#c5b0d5"
        ],
        "outputs": 1,
        "useDifferentColor": false,
        "className": "",
        "x": 620,
        "y": 200,
        "wires": [
            []
        ]
    },
    {
        "id": "9e7148d9a5fcbfae",
        "type": "bar-chart-data2",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "bar-chart-data2",
        "x_interval": "days",
        "x_size": 24,
        "unit": "c",
        "precision": 2,
        "is_meter_reading": "False",
        "agg_by": "max",
        "x": 420,
        "y": 280,
        "wires": [
            [
                "b6ed25afa97b9f26"
            ]
        ]
    },
    {
        "id": "b6ed25afa97b9f26",
        "type": "ui_chart",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "",
        "group": "b5f7f90a2f77ea3d",
        "order": 1,
        "width": 18,
        "height": 5,
        "label": "highest outside",
        "chartType": "bar",
        "legend": "true",
        "xformat": "HH:mm:ss",
        "interpolate": "linear",
        "nodata": "",
        "dot": false,
        "ymin": "",
        "ymax": "",
        "removeOlder": 1,
        "removeOlderPoints": "",
        "removeOlderUnit": "3600",
        "cutout": 0,
        "useOneColor": false,
        "useUTC": false,
        "colors": [
            "#1f77b4",
            "#aec7e8",
            "#ff7f0e",
            "#2ca02c",
            "#98df8a",
            "#d62728",
            "#ff9896",
            "#9467bd",
            "#c5b0d5"
        ],
        "outputs": 1,
        "useDifferentColor": false,
        "className": "",
        "x": 600,
        "y": 280,
        "wires": [
            []
        ]
    },
    {
        "id": "5ae30d57abb32fac",
        "type": "smooth",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "lowest",
        "property": "payload",
        "action": "min",
        "count": "10",
        "round": "",
        "mult": "single",
        "reduce": false,
        "x": 270,
        "y": 200,
        "wires": [
            [
                "8dc4a744a869b740"
            ]
        ]
    },
    {
        "id": "5269df838f656cd0",
        "type": "smooth",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "highest",
        "property": "payload",
        "action": "max",
        "count": "10",
        "round": "",
        "mult": "single",
        "reduce": false,
        "x": 260,
        "y": 280,
        "wires": [
            [
                "9e7148d9a5fcbfae"
            ]
        ]
    },
    {
        "id": "6eaf9754b1bf4d38",
        "type": "show-value",
        "z": "d3637ed3c66aa0d7",
        "g": "558a976d1540e55c",
        "name": "",
        "path": "",
        "x": 190,
        "y": 340,
        "wires": [
            []
        ]
    },
    {
        "id": "dc0340c9643bd396",
        "type": "mqtt-broker",
        "name": "",
        "broker": "192.168.0.107",
        "port": "1883",
        "clientid": "",
        "autoConnect": true,
        "usetls": false,
        "protocolVersion": "4",
        "keepalive": "60",
        "cleansession": true,
        "autoUnsubscribe": true,
        "birthTopic": "",
        "birthQos": "0",
        "birthPayload": "",
        "birthMsg": {},
        "closeTopic": "",
        "closeQos": "0",
        "closePayload": "",
        "closeMsg": {},
        "willTopic": "",
        "willQos": "0",
        "willPayload": "",
        "willMsg": {},
        "userProps": "",
        "sessionExpiry": ""
    },
    {
        "id": "b5f7f90a2f77ea3d",
        "type": "ui_group",
        "name": "Group 1",
        "tab": "eaa84631f407bcd4",
        "order": 1,
        "disp": true,
        "width": "18",
        "collapse": false,
        "className": ""
    },
    {
        "id": "eaa84631f407bcd4",
        "type": "ui_tab",
        "name": "daily temperatures",
        "icon": "dashboard",
        "order": 5,
        "disabled": false,
        "hidden": false
    },
    {
        "id": "0d746eb07550f0f5",
        "type": "global-config",
        "env": [],
        "modules": {
            "node-red-contrib-dashboard-bar-chart-data2": "0.9.101",
            "node-red-dashboard": "3.6.6",
            "node-red-node-smooth": "0.1.2",
            "node-red-show-value": "1.0.4"
        }
    }
]

```

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/a/2/a2ee1e77f31b9c27fa5bf19aa9a67840218d0a78.png)

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [4 December 2025 23:01 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/38 "2025-12-04T23:01:56Z")

</div>

really appreciate all the help thanks  
martin

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [5 December 2025 05:34 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/39 "2025-12-05T05:34:55Z")

</div>

No problems.

I don't mind helping. Though from what I am reading it isn't really helping you.

Mind posting that `function` node's code again?  
I know I wrote it, but it would be better you post it to me as I am not sure where it is and I have LOT of tabs. Find it may not be as easy as you think.

(Sorry. Scrolled up and found it.)  
Silly me.

Hang on while I test things.

# UPDATE:

Sorry, just asking:  
**Excluding** the `mqtt in`, and `chart` nodes, please export the flow you have.

Rather than the `mqtt in` node, add a few `inject` nodes with values like:  
1, 10, 20, 30, 40, 50  
Replacing the `chart` nodes (or `template` nodes) add `debug` nodes that display the same data as used by the `chart/template` nodes.

Note:  
the OUTPUT from the `function` node is not _SIMPLE_.  
Rather than the `payload` you have to use `msg.max` and `msg.min` for the maximum and minimum values.  
Sorry.  
The payload is the value.  
The `msg.max` and `msg.min` are the stored values included in the message just for the fun of it.  
Which is kind of handy anyway.

Looking at the two charts/graphs/what ever.....  
Yeah, you are getting values for 12 of Jan, 12 Feb, 12 Mar 12 April.....  
Oh, sorry.  
1, 2, 3, 4 December.  
5 December isn't included but I'm not sure it has become 5 December when you posted it, and there is/was any data received.

Sorry.  
I did a bit of tweaking but at this point it is not mission critical or really changing the output anyway.

Later on I'll post the newer one once we get out heads around what's going on.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [5 December 2025 06:05 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/40 "2025-12-05T06:05:08Z")

</div>

New bit of code anyway.

I am still not sure I am completely understanding you need.  
(My bad.)

This maybe is more what you want.  
Dunno.

```auto
let old = context.get('Day')
let day = new Date().getDay()

//----
// test block here
if (msg.payload == 'TEST')
{
    node.warn("Resetting for new day")
    context.set('Day', day)
    context.set('Min',10E6)
    context.set('Max',-10E6)
    msg.min = [] // edited
    msg.max = [] //edited (Sorry)
    return
}
// end test block

if (old != day)
{
    node.warn("Resetting for new day")
    context.set('Day', day)
    context.set('Min',10E6)
    context.set('Max',-10E6)
    msg.min = [] // edited
    msg.max = [] // edited
    return // This may actually not be needed when the day changes.
               // We'll work on this later.
}else
{
    msg.min = context.get('Min')
    msg.max = context.get('Max')
}

if (msg.payload < msg.min) 
{
    node.warn("new min")
    msg.min = msg.payload
    context.set('Min', msg.min)
    return msg
}
if (msg.payload > msg.max) 
{
    node.warn("new max")
    msg.max = msg.payload
    context.set('Max', msg.max)
    return msg
}

```

It has a quick that it needs 2 messages to establish the max and min values.  
But again: you are losing ONE (well ok: TWO) messages to establish things.  
Actually THREE if you are not sending a newday message. (`TEST`)

## UPDATE:

See the comment on the `return` line. It may be deleted if you are getting the readings as this is/would/should be a valid new value. As is, I dropped the message, but in retrospect, it may be ok to delete the `return` line.

---

<div class="post-metadata">

**Author:** ![montyfert](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@montyfert](https://discourse.nodered.org/u/montyfert)\
**Post date:** [5 December 2025 20:39 UTC](https://discourse.nodered.org/t/trying-to-chart-high-low-temp/99775/41 "2025-12-05T20:39:26Z")

</div>

thanks i]ll give it a try  
martin

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