EPW file error, issues with sunpath 1. Solution exception:hour must be in 0..23: (6/21@24:22)(m/d@h:m)

Hi guys,

Seems like this is a recurring issue with Icelandic EPW files. I found a couple of discussions highlighting my particular problem but so far no solutions yet.

I’m trying to do some site analysis on Grimsstadir, Iceland. Like many others, Sunpath in LB is having trouble with the EPW file with the specific error code of

  1. Solution exception:hour must be in 0…23:

    Here’s the website I used to download the EPW file: \climatewebsite\WMO_Region_6_Europe\ISL_Iceland
    and specifically the zip file named ISL_NE_Grimsstadir.040730_TMYx.2007-2021.zip

I can’t upload the file since I’m a new user, but any help will be appreciated!


Thanks for finding and reporting the issue, @az0311 .

This is, indeed, a bug. It only affects locations where it is possible to get a sunset after midnight (or sunrise before midnight). I guess we had thought that such situations were not possible and, if we were strictly using solar time, they would not be. But it seems that after-midnight sunsets can happen in places that lie directly along the arctic/antarctic circle where the time zone shifts the sunset from solar time just enough to cause an after-midnight sunset, followed by a sunrise a few minutes later.

In any event I just pushed a fix for this to the latest development version of the plugin:

You can get the fix you your end with the LB Versioner in an hour or so. After that, I have no issues making a sunpath for your location in Iceland:

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