ClimaCell Weather Forecast API

I’ve been looking at alternative weather forecasting API’s now that DarkSky are closing theirs and came across climacell:

Their free tier is very generous and there are a large number of weather fields that can be requested including: ‘Solar radiation reaching the surface’ which looks like it could be really useful for solar forecasting.

The API builder provides clear examples of how to build requests using different programming languages.

Im only just trying this out so I dont have any experience on the accuracy of the forecasts but thought I’d share as it looks great!

Python example

import requests

url = ""

querystring = {"lat":"53.179777","lon":"-4.058699","unit_system":"si","start_time":"2020-05-20T14:00:00Z","end_time":"2020-05-20T20:00:00Z","fields":"surface_shortwave_radiation,temp,wind_speed,precipitation","apikey":""}

response = requests.request("GET", url, params=querystring)


On closer inspection the solar prediction provided does not seem to be correct, its predicting 350W at 1am and the shape is not right, I’ve emailed ClimaCell to ask about it.

I’m getting much better results from Solcast: thanks to @icenov for the tip Importing NREL Solar Models in to EmonCMS - #24 by icenov

I noticed the same behaviour with ClimaCell, which I thought was timezone related. I tried adjusting the timezone to UTC+09:00 etc but still couldn’t make any sense of it. Interested to hear what their response is…

I assume that max solar radiation is know for every location in the world of every day.
And so pvoutput makes a daily prediction for my solar max with my specific pv setup.
Lastly I needed a new api for temperature and had a free account at Weather API - OpenWeatherMap
I also found out that there you can get free hourly predictions of the cloudiness in % for 48 hours ahead. (Or 5 days at 3-hour intervals.)
That combined could be a solar forecast?

Not sure if cloudiness here means ‘cloud opacity’.

And also temperature and the type of clouds play their role ofcourse…

yes @peter gives an example of using a cloud forecast with a clear sky forecast here Importing NREL Solar Models in to EmonCMS - #7 by SolarMill

I’d like to look at that approach a bit closer too.


@TrystanLea , is this usefull too? Electricity data