IN meteorology the winter months are December, January and February, although the official start of winter, (the winter solstice or shortest day) is around the 21st/22nd December. Afterwards the days very slowly become longer, but as the winter moves on the weather often gets colder with a greater chance of frost and snow.

Due to global warming our winters are much milder than they were a decade or so ago, with very few wintry snaps, although winter 2008/2009 turned out to be one the coldest for a good few years. It is not until late November or even early December before the first real frost arrives. During some years November and December can be frost and snow free, especially if the milder winds from off the Atlantic is blowing into Britain from the south or south-west as they are this year (2009). When the upper jet stream is pumping strongly into the UK, we experience gales, heavy rain, flooding and milder temperatures. In some years these conditions prevail bringing us a mild winter.

Next Week: Onset of Winter Part 2

Glossary: Black Ice: Transparent ice that forms when liquid water on the ground freezes, for instance when the temperature falls sharply after rain.

Weather for coming week Monday 23rd November-Friday 27th November

Atlantic winds influencing the weather over this coming week.

Monday, Wednesday, Thursday and Friday brings sunshine and a scattering of sharp showers. Tuesday cloudy and damp with some rain about. Staying windy this coming week with west/south-west winds gusting between 30 and 50 mph at times, somewhat less strong on Friday.

So, with no prolonged heavy rain this week, the river levels will start to recede.

Maximum temperature 10-13c 50-55f.

Minimum temperature 4-8c 39-46f.

Last Week's Observations (Monday-Sunday)

Highest day temperature........15.4c on Friday 20th November

Lowest night temperature........6.1c on Friday 20th November

Wettest day...........................8.5 mm on Saturday 21st November