What a terrific moon halo in Reading this evening! Best I've ever seen and great to look at! Unfortunately it's hard to capture with any normal camera.
I believe it's something to do with the moon's light refracting off ice crystals, creating the halo, where the sky within is actually darker than the rest of the sky. It is also suggestive of precipitation in the next few hours which as the radar shows will be snow! Unfortunately the blob in the radar right now will begin to fizzle out and become much more showery in nature so max 1 or 2 cm here. But any snow falling won't have trouble settling after a freezing cold day. Just a shame the snowfall has to be at 3 in the morning again!