SUDDEN and extreme swings in the weather, characteristic of the past year or so, were again in evidence during February. This time there was a mild, wet and windy start and finish, either side of a dry, calm, clear and frosty interlude lasting over a fortnight.

The dry spell was due to a huge area of very high pressure that began near the Low Countries around the 6th and produced a gentle, southerly drift across Britain. This gave temperature ranges between sunrise and the early afternoon that were remarkably large for February and more typical of early summer. The peaks reached were more worthy of April, too.

For example, on the 12th, from about freezing at 8am, a few spots topped 60F (15.5C) six hours later.

The oscillations were mostly due to mixing of the air rather than the strength of the sun, still weak in February. After dawn, as the breeze picked up, turbulence brought down mild air from aloft to displace the cold layer that formed at the surface overnight.

With cloud-free skies, inevitably fog plagued some locations. Unusually, to begin with on Sunday the 10th, it affected some of the coastline. So in this respect as well, there was a hint of the traditional North-East summer - sunny and warm inland, but with a fret making it dull and chilly at the seaside.

After a week, winds backed to the south-east and it became colder, but with the big differences between maxima and minima continuing.

Here at Carlton, near Stokesley, the lowest, early on Wednesday the 20th, of -9C (15.5F) in my thermometer screen and -11.5C (11.5F) on the grass, were the coldest I've measured since March 3rd, 2001.

My record for February, or any month, occurred on February 11th, 1986. Then the mercury plunged to -15C (5F) in the screen and to -18C (-1F) over snow. Had there been a covering of snow this February, these figures could have been at least equalled.

More notably, perhaps, also on the 20th, the 10cm (4ins) soil thermometer sunk to -1C (30F). This was its lowest reading in my 20 years of data that I have for this instrument - rare in these days of global warming. It beat the previous one, -0.8C (30.5F) on January 29th, 1992, and probably would have been lower than in February 1986.

This suggests the cold snap was one of the longest, with clear skies and without snow in two or three decades. The decline in the ground temperatures showed that far more radiation was being lost to space than was gained via all the sunshine. This confirmed, undeniably, that it was still winter.

A layer of snow provides an insulating blanket and keeps soil relatively warm. Heat rising from below is unable to escape and help warm the air next to the ground. Temperatures, therefore, drop like a stone on cloudless calm nights, as they did in both February 1986 and early March 2001. Without snow this time around, the ground froze, but temperatures in the air didn't fall to the depths they might have done.

Overall, the month was mild, cool at night but much above average by day, with maxima widely the highest in February since 2002.

With about half the usual rainfall, it was the driest February across most of the region for five years - ten in one or two places. However, a few very wet days in parts of the Dales boosted totals over the norm.

Sunshine was plentiful, on the verge of double the mean. Let's hope, as April offered the best "summer" month last year, it's not going to be February this year!

The very changeable weather that predominated during January persisted into February for the first five days and returned for the final week or so. Depressions once more passed close to Scotland, bringing belts of often heavy rain across Britain; one on Friday 1st tracked over northern England.

As we largely stayed on the northern side of this system, there was much snow lying even at low levels and causing chaos on higher routes, particularly the A66. It didn't last, with milder air flooding back across the country by the next day.

February temperatures and rainfall at Carlton-in-Cleveland: mean max: 9.0C, 48F (+1.9C, +3.5F); mean min: 0.9C, 33.5F (- 0.5C, -1F); highest max: 13.9C, 57F, 9th and 12th; lowest min: -9.1C, 15.5F, 20th; total rainfall: 30mm, 1.15ins (-22.5mm, -0.9ins); wettest day: 12mm, 0.45ins, 4th; number of rain days with 0.2mm (0.01ins) or more: 7 (-7). Figures in brackets show the difference from the 24- year mean, 1984-2007.