# How can I add precipitation data to an existing weather file? [closed]

Hi everyone, I am studying the performance of a green roof in Opestudio but I have some problems since the weather file I am using to run the simulation doesn't have any precipitation data. I tried to modify the weather file I'm working on but, even if I add rainfall value different from zero in the epw file, it seems like nothing has changed. It seems like, even though I add rainfall data in the epw file, the program still doesn't read them. I tried to modify the epw using excel and also manually, but it doesn't work both ways. I also tried to use elements but I didn't find a column in which I can change the precipitation data. So, basically my question is: Why even though I changed the rainfall data from 999.0 to data the 10 mm/h the software still doesn't read them? How can I correctly add precipitation data to an existing weather file in order to evaluate green roofs performance?

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### Closed for the following reason duplicate question by Aaron Boranian close date 2018-12-19 11:50:06.538638

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@alepelu92 this is a duplicate question of this post. Essentially, rain fall amounts in the EPW file are not used. You should use the Site:Precipitation object to evaluate your green roof.

( 2018-12-19 11:51:06 -0500 )edit

Thank you so much! Actually I am working with Openstudio instead of EnergyPlus. If I set the precipitation site field in EnergyPlus how can I apply the same ammount of precipitation in Openstudio? I tryed importing the Idf file in Openstudio but it doesn't work.

( 2018-12-20 03:42:40 -0500 )edit

@alepelu92 sorry that I didn't catch that! I see that you've opened up a new post for this question of applying precipitation in OpenStudio, so I'll keep this one closed.

( 2018-12-21 11:22:47 -0500 )edit