Forecast for the rest of Winter 2009/10

Temperature

For the rest of winter, over northern Europe including the UK, the chance of colder conditions is now 45%; there is a 30% chance of average and a 25% chance of milder conditions.

Rainfall

For the rest of winter, for northern Europe including the UK, there are near-equal chances for each of the three categories. There is a 30% chance of a drier winter, a 35% chance of an average winter and a 35% chance of a wetter winter.

What do we mean by colder, near-average and milder

The UK average temperature for December to February for the period 1971–2000 is 3.7 °C. A milder winter in the UK is defined by winter-mean temperatures greater than 4.3 °C, near-average by temperatures between 3.4 °C and 4.3 °C and colder by temperatures lower than 3.4 °C.

What do we mean by drier, near-average and wetter

The UK average for December to February for the period 1971–2000 is 332 mm. A wetter winter in the UK is defined by precipitation totals greater than 336 mm, near-average by precipitation totals between 294 mm and 336 mm and drier by precipitation totals below 294 mm.

Our methods

We use global forecasting models and statistical methods. Seasonal trends affect large geographic areas, so our forecast for the UK is in the context of Europe as a whole.

Background

Winter, in this context, is defined as the months of December, January and February — although it is recognised that winter weather can extend beyond this period. As normal during December, January and February, we can expect some colder spells of weather this winter.

For the UK, winter last year was in the colder category with a mean temperature of 3.2 °C, and in the drier category, with 260 mm of precipitation (78% of the average).