WHAT on earth is happening to our weather? January was some 30 per cent wetter and two degrees Celsius warmer than average; February has so far been one of the warmest since records began. In Bournemouth, people have been seen swimming in the sea, and there were traffic jams as people headed for the coast in unprecedented numbers over the St Valentine's weekend.

Now cast your mind back to last year. January 1997 was the driest for 200 years and the coldest for 10 years. February was generally mild and windy, though north-west England and southern Scotland had three times as much rain as usual.

With the irrationality of people who bet on lottery numbers that haven't been picked for a long time, we might have expected a particularly cold February - as though winter would gain revenge for its late arrival. But it hasn't happened.

There are three theories to explain what's been going on. The simplest is to shrug it off as all within the bounds of normal fluctuations of weather. With every new broken record, however, that becomes more difficult to sustain. In Paris, for example, a new record February temperature of 17.4C was set a couple of weeks ago, a full 2.4C above the previous record. Such a dramatic increase demands explanation.

The second theory is global warming. The Earth is getting warmer because of all the greenhouse gases; so England is getting warmer too. Simple. But it's not so simple. The most extravagant predictions of global warming envisage a rise by only a few degrees in a century, and while a few degrees over the entire Earth can make a huge difference in specific locations, no mechanism has yet been suggested that would account for our balmy February weather this year. Indeed, there is a good argument that global warming would actually make Britain a colder place because of the Arctic melting it would induce.

Finally, and most likely, there is good old, blame-it-for-everything, El Nino, which has been warming up the waters of the Pacific and might be expected to have a strong, but as yet not understood, influence on the south-westerly winds that have been fighting off the easterlies and northerlies that so often seize us in their icy grip in February. On the other hand, global warming itself may be responsible for the ferocity of this year's El Nino; or it could be that the current El Nino is no more than a random fluctuation worse than any other El Nino.

The extremes of 1998 will surely lead to an improvement in our understanding of global weather patterns. The question at the beginning of this piece ought not to have been "What on earth ..." but "What in the ocean" is happening to our weather.