Already reported here but I now realise that may be the wrong place.
https://community.windy.com/topic/4989/zoom-level-bug-errors-which-temperature-forecast-is-correct

Also reported Nov 2017 by a different user.

e.g.
https://www.windy.com/?55.388,-3.780,10
Sanquar 2, Leadhills 2 - degrees
https://www.windy.com/?55.388,-3.780,11
Sanquar 4, Leadhills 4

Just encountered this, so it is still occurring.

e.g.
https://www.windy.com/?55.388,-3.780,10
Sanquar 2, Leadhills 2 - degrees
https://www.windy.com/?55.388,-3.780,11
Sanquar 4, Leadhills 4