Deviation to the average temperature. So its 13 K above the average. Or in other words around 42-44°C

Edit: oh you were complaining about the colormap? Yeah its super shit

Havent worked with this explicit hotwire air speed sensor, but we used some in the lab while I studied.

Without proper calibration (e.g. good reference wind speed) they are pretty much useless. Unless you just wann know strong wind or no wind. If you have good calibration then hot wire air speed sensors are a good way to measure wind speed.

Nah, there is no data for the baltics.

Let me introduce you to the phoney war: https://en.wikipedia.org/wiki/Phoney_War Pretty much nothing happened until May 1940.