Forecast solar is way off

Hi All,

I am trying to write some code on how to decide when to charge my boiler. For this I would like to use solar forecast data from forecast.solar. However, it does not predict things that well.

Off course I set the

  • Declination in forecast.solar (51 degrees)
  • Azimut in forecast.solar (245 degrees)
  • Total Watt peak in forecast.solar (4455W)
  • Inverter size in forecast.solar (3254W)
  • My home location in home assistant, zones

For your information, my house is somewhere in the middle of the Netherlands

Is this normal?

Edit:
That was not the best graph.
Here is a better one.

Your predictions are actually more precise than the ones I manage to get :wink:

O dear. That’s not good :stuck_out_tongue:
To be honest, you should not look at a single day. Every now and then there is a day where the prediction is way off. It is not always clear where the edge of big clouds are going to be.

I just think their forecasts are not good.
Tbh, the only weather provider giving me decent forecasts is my country-specific one

It certainly is for myself.

https://community.home-assistant.io/t/getting-data-from-solar-forecasts/497286/8?u=biscuit

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There are threads on the forum for alternative solar forecast Integrations…have a search for Solcast and/or OpenMeteo Solar and you’ll get the details…

Solcast…a lot to read in here (start from BJReplay repository posts since May 24)

There’s also a REST sensor config in this thread for Solcast data

OpenMeteo Solar

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Thanks. I will look into these topics.

@Biscuit
That is beautiful data! Nice work :slight_smile:

Perhaps good to mentions how does turned out.
I am using Solcast now. It is so much better than forecast solar. Here are some examples.

Easy day

More difficult day with clouds every now and then.

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