Creating a custom EPW for annual clear sky radiation analysis


I would like to run an annual analysis with clear sky conditions. Is there a tool that allows you to edit the EPW file within grasshopper?

Has anyone been successful in generating this type of sky?

I have tried converting to CSV and editing the file in excel - converting back to EPW…but do not trust the results.

Any help would be much appreciated.


Hi @JMS,

Please have a look to this. There is an example file attached by Chris. Thanks

Thanks @MohammedAlshayeb!!

Also, if you have not used HB+ yet, I recommend starting with this example file:,0
… which runs a radiation analysis using a clear sky.

The link that @MohammedAlshayeb posted shows how to create the EPW with the clear sky, though.

thanks @chris, much appreciated!