Any astronomers amongst us?

[janeyo]

Bummer. I missed it.

[Mike and Louise]

The halo around the Moon is simply caused by the moon light passing through either ice crystals or water vapour in the Earth's atmosphere.

It is similar to the way that the Sun creates a rainbow when it is either raining or there is a lot of humidity.

And, just like a rainbow, you can sometimes see the 7 colours in the Moon's halo too. But the halo needs to be very bright in order to see it.

[Capsid]

Venus is a spectacular sight at this time too because it is nearly at its closest to earth (20th Feb). Look to the South West at dusk and you can't miss it.

[pjh75]

So it seems I am the only person to have never seen / heard of it... well they say you learn something new every day.

[Growem]

You can get them around the sun too, for the same reason of ice crystals. You see them all the time in the winter in Canada because a) it's colder and b) it's sunnier. We'd call them sun dogs, although that apparently just refers to a bright spot on the halo, rather than the actual halo.

[terrier]

sun dogs - Google Image Search