@schilpat
Thanks for your replies.

I changed the Firefox mysterious "gfx.color_management.mode" from 2 back to 1 (which is the default), and the checkerboard has now disappeared.
Sadly, color management now doesn't work correctly in the browser, which it appeared to do on setting '2'.

So I suppose this is a solution for viewing Windy, but it would be nice if it also worked with the "gfx.color_management.mode" set to 2.

Edit: Somehow this "gfx.color_management.mode" setting appears to be back at '2', and the checkerboard has not returned, so it's possible some legacy setting was messing things up.

As an aside, there is a lot of info about Firefox color management online, and while it's possible to make it behave differently, it never seems to work correctly.

@idefix37 Great.
In case it helps, it's been this way for several months - since before the timebar was updated.
It did work perfectly well previously, but I don't remember when it changed, or whether it was related to a Windy update or a Firefox or driver update.
Let me know if I can provide any information to help.

@idefix37
'No errors' reported in the Windy console.
WebGL is enabled and running in Firefox, as far as I can tell.

@idefix37 thanks for your reply.
This is a typical view - the checkerboard is more obvious in the daylight section, but it's always there.
It's the same with Radar on or off.

As title. It's been like this for a long time. Using Firefox 145.0.2 in Windows 10.
If I subscribed to the Premium version, would this change?
I'm not interested in the 'App', only the website version.