Wind arrows disappear and reappear each step

[jidanni]

• Go to https://www.windy.com/-Rain-thunder-rain?gfs,rain
• Keep your eyes on the little wind arrows
• Start the animation

Wouldn't it be better to keep the previous hour's arrows on the screen while drawing this hour's?

Currently the user sees the arrows totally disappear and reappear for each step. Well at least the background tiles don't do the same.