Openweathermap has a "new" (don't know actually how new that is) API that provides data more similar to dark sky.
- Current weather
- Minute forecast for 1 hour (did not work for me in Europe)
- Hourly forecast for 48 hours
- Daily forecast for 7 days
I think the output of the daily forecast is more useable than the 5*8 output of the old forceast API.
Maybe node-red-node-openweathermap could be updated to also use this API, but doing a http request is easy enough.