The south-westerlies that dominated November continued to blow for a few more days.

These drove increasingly energetic, frontal systems across Britain on alternate days.

The 5th saw a vigorous depression sweep across our region giving a very wet day - for most the wettest day of the month. Behind this, pressure rose dramatically, heralding a major change in the weather pattern. A large high pressure area developed and was to govern the charts for the next fortnight.

Although dry and with very light winds, conditions varied enormously from day to day according to where the anticyclone was centred. Initially, it was positioned over southern Scandinavia, giving us a southerly breeze. It was fine and sunny, with slight frost at night. Fog became an increasing problem, persisting all day in some places by the end of the second week-end. This dispersed by Tuesday the 11th, as drier air briefly came in from the Continent.

Sub-zero temperatures had spread across much of Europe during the week before this. As the high moved slowly west into the northern North Sea, winds turned easterly later the next day and this bitter cold edged into south-east England.

For us in the North-East, it was tempered by the longer sea track, so the only difference we noticed was that it became cloudy. This thickened over the next day or two, to give a spell of "anticyclonic gloom". A little, light drizzle accompanied this, especially on Saturday the 12th, with occasional showery bursts of rain as well from the Sunday for a few days.

These gave some appreciable falls of rain, two or three millimetres (in the order of a tenth of an inch) each day - modest by normal standards, but remarkable in view of the height of our barometers. These were indicating "very dry", but the inscriptions on them should never be taken too literally.

The high continued to slip away westwards, allowing fronts to move across the country every other day or so for the remainder of December. The wind oscillated from about south-westerly ahead of these, to more northerly behind them. There was rain at times as the fronts passed by, with a gale in exposed areas on Friday the 28th. Following them, the weather depended on how far into the north the breeze veered.

Due to the shape of the North-East coast-line, the direction is crucial at this time of the year when showers form so readily over the sea. They die out rapidly as they come in land, especially when they cross the hills.

With a west to north-westerly, the air comes across the land and beautiful, sunny days result. Once the airstream turns north-north-west, wintry showers blow down the coast and affect places east of a line extending south from Middlesbrough. If the wind becomes due north, there's a potential sea-track straight from the Arctic.

Heavy snow and hail showers pile in roughly east of the A1, as they did on Saturday the 22nd and again on Sunday the 30th. On the 22nd, they gave up to ten inches on the north-east side of the North York Moors. It is only when the wind veers to the north-east do they reach the west of our region though sometimes these parts do receive some dying showers passing over the moors from the west.

Overall, the month was very sunny, on the dry side, particularly towards the Pennines, and cold - distinctly chilly at night, owing to the abundance of clear skies. It was the coldest December since 1996. December 1995 was much colder still, by 1C (2F), though we had six more air frosts this year, by far the most in any December in my 19-year record here at Carlton, near Stokesley, but they were largely relatively slight.

DECEMBER TEMPERATURES &

RAINFALL at CARLTON-in-CLEVELAND

Mean max: 6.2oC, 43oF, (-0.9oC, -1.6oF); mean min: 0.2oC, 32.5oF, (-1.9oC, -3oF); highest max: 10.2oC, 50.5oF, 1st; lowest min -7.4oC, 18.5oF, 31st; total rainfall 63mm, 2.5ins, (-4mm, -0.15ins); wettest day 14.5mm, 0.6ins, 5th; no of rain days, with 0.2mm (0.01ins) or more: 5.

Figures in brackets show the difference from the 19-year mean, 1984-2001.