Exactly what I was thinking. Comparing it with https://www.ventusky.com/?p=26.8;-117.1;4&l=wind-10m it’s almost identical.

This was brought up in an old thread about windy: https://news.ycombinator.com/item?id=15095654

It looks remarkably similar. One must be a copy of the other. I was aware of Ventusky first but doesn't necessarily mean it came first.