What's behind the current cold snap?

Snow on the Pennine tops at Saddleworth Moor near Manchester following a week of frosts and snow. Credit: PA

It's another bitterly cold day today. But why so cold?

It's all down to where the air originates from. Today's can be traced back to Russia.

Russia is always cold at this time of year but in the south it's around 20 degrees below average. Overnight it will be as low as -40C and by day might not get above -30C! Wow that is cold!

How about us? Clear starry skies meant temperatures overnight were as low at -10.5C in Tulloch Bridge, -6C in Katesbridge, -5C in Exeter and Trawscoed.

There will be lots of hoar frost, so lots of windscreens will need scraping, plus icy stretches in the east, where we still have a few wintry showers and areas of fog.

We could see similar temperatures again tonight. The risk of even more extensive freezing fog developing. This will be dense and very stubborn to clear, lingering all day for some! So take care on the roads.

What next? Then the weather does a 180 turn and by the end of the week milder air fights back from the Atlantic bringing the return of wet and windy weather. The heaviest rain will be in the south west where we could see local flooding.

What a week of weather!