Tag Archives: circumzenithal arc

Cold weather sky

Friday 15th June 2018, 6.40pm (day 2,486)

Cold weather sky, 15/6/18

With mare’s-tails spread all over the sky and a circumzenithal arc showing off the ice crystals in the upper atmosphere… I think the recent warm weather might be coming to an end. Still, that’s an English June for you.

Tagged , , , , , , ,

Ice rainbow

Thursday 29th August 2013, 6.30pm (day 735)

Ice rainbow 29/8/13

I’ve only ever seen this a couple of times before — a rainbow, or at least a spectrum, high in the air, nowhere near the ground and with no rain in sight. I guess it must be caused by light refracting through ice crystals in the upper atmosphere. Bad weather on the way perhaps. Let’s hope not: I intend to spend next weekend walking in Norway.

POSTSCRIPT: Have discovered this is something called a ‘circumzenithal arc’. They are not rare as such, but apparently only appear when the sun is at exactly the right angle to ice crystals in high-level clouds, and thus can be seen only in very restricted locations on the ground. So if you do see one, feel privileged – it may well only be visible in a space a few metres around you.

Tagged , , , , , , , , , ,
%d bloggers like this: