Literally took my hours trying to fix this problem, until I found this post. Added some .png files to the project and started getting this error. Running xattr -c fixed it. I am really pissed of lack of information for this error.

A "forecast" is supposed to give you data in the future, not in the past. Always starting at midnight is an unnecessary complication. It should start at the current hour, like it was in the darksky api. Bad decision to change that.