I can’t seem to find the original source, but based on search results, I’m seeing that this map has been circulating in similar circles to this and solar power communities since at least 2016.
The American one seems to match this, which has “National Climatic Data Center’s U.S. Stations 1961-1990 Monthly Normals for the Atypical Climate Elements” as its source.
The European one seems to be from this Wikimedia Commons user, but they never specified their source beyond “according to national data”
I can’t seem to find the original source, but based on search results, I’m seeing that this map has been circulating in similar circles to this and solar power communities since at least 2016.
The American one seems to match this, which has “National Climatic Data Center’s U.S. Stations 1961-1990 Monthly Normals for the Atypical Climate Elements” as its source.
The European one seems to be from this Wikimedia Commons user, but they never specified their source beyond “according to national data”
This is the sauce every map needs. Thank you.