P.S. discovered a workaround: simply switching to a different tab, and then switching back to the Windy tab, makes the arrow keys work again.

However, if I close that Windy tab and then open Windy afresh, the right arrow key stops working again.

(Interestingly, the right arrow key does always work once [advance the time view by one interval], then it stops working.)

The above workaround seems to be successful 100% of the time, so I'm happy with that.

That happens for me too - Google Chrome 121.0.6167.86 64-bit, Windows 11 Pro. Just started happening a few days ago.

Tried deleting my cookies for Windy and that didn't help.

Tried Windy on Edge 121.0.2277.83 and the right arrow key worked.

This problem seems to be specific to Windy. Other web applications that support the arrow keys, such as Google Maps, still work fine in Google Chrome.