Windy was coded by billionaire founder and owner of Seznam, which is czech search engine (and media company), one of only three other search engines in the world that still beats Google in local market.
Seznam is a remarkable company. Their maps (http://mapy.cz) are second to none, my favourite feature are touristic maps which work at least within Europe.
Though for windsurfing I find windguru.cz is more useful (also Czech(!)) and for flying its hard to beat ForeFlight.
It should also be clarified that Seznam is one of the few companies to beat Google in searches with the Latin alphabet. Local search engines are still beating Google in Chinese, Korean, Japanese and Cyrillic alphabets.
[1] https://www.forbes.com/sites/forbesinternational/2017/02/06/...
https://mapy.cz/zakladni?x=16.6075148&y=49.1942864&z=19&m3d=...
https://www.google.cz/maps/@49.1926496,16.6076641,133a,35y,2...