Barbecues and sunbathing were the order of the day when Britain enjoyed some of its hottest-ever February weather at the weekend.

On Saturday the 16.6C (61.9F) heat in London broke records held for February 9 for more than a century. The last time temperatures neared that level on that day was 105 years ago, when it was 16.3C.

Yesterday the temperature again broke the 16C barrier at the Royal Botanic Gardens in Kew. Climate experts there expect the blooming of flowers to surpass the premature dates recorded last year. The opening of their daffodils occurred on January 16, a week before 2007 — and 11 days before the recent average. The English hawthorn is expected to flower by the end of the month, more than eight weeks before it normally would. Crocuses opened 11 days in advance of the past decade’s average.

Since 1952 Kew has recorded when different flowers open, about a hundred being monitored, with year-on-year changes tracked. Early blooms indicated that climate change was having an increased impact, Nigel Taylor, the curator, said.

The bloomings “are months earlier than the norm, and given that they are species that have evolved in the vagaries of the English climate, the more remarkable because one would expect them not to react so easily to milder weather in winter”, he said. “This suggests the changes in our climate are more far-reaching than previously seen.”

Mild southerly air swept up from North Africa and the mid-Atlantic on a powerful anticyclone that also gave glorious blue skies. The warmth spread across Britain, with North Wales close to breaking a temperature record as warm air spilt down the mountains in a föhn wind effect, better known in the Alps where winds down mountainsides become compressed and heat up like a bicycle pump.

The signs are for an early spring getting under way in many places. Last month was the ninth-warmest January on record with an average temperature for central England of 6.6C (43.9F), in archives going back 349 years. So far, February has continued unusually warm, 2C (36F) above normal, with frogs spawning and birds nesting. Parts of England and Wales have seen hardly a snowflake all winter, and although cold snaps could return, the long-range forecasts point to more balmy days. There is little sign of the savage Arctic winter that had been predicted late last year.

Although last month was one of the wettest Januarys on record, this month could turn out unusually dry. February is usually our driest winter month, but this winter may be following the pattern of 1948, when the wettest January on record in England and Wales was followed by a dry February and spring.

This winter is panning out much as the Met Office had predicted, with a coldish December giving way to warm weather later on. Much of its forecast was based on the La Niña phenomenon in the tropical seas of the Pacific. The sea temperatures there are some two degrees colder than normal over an area the size of the US, and that has sent global weather patterns haywire. Huge storms have ravaged California, eastern Australia and southern Africa, while unusual heat in the southeast United States helped to produce the devastating tornadoes seen last week.

La Niña also hits the jet stream, a ribbon of winds a few miles high that have helped to steer mild air our way.

Floods bring rats

Britain is facing a plague of rats because of changing weather. Online inquiries to Rentokil have risen by 300 per cent, with reports of more and larger rodents.

Killgerm, the country’s biggest supplier of rat poison, said that its sales rose by a quarter in 2007.

Longer summers mean more time for rats to breed and give them greater access to food. The summer floods forced them out from underground, with many invading houses.

Rentokil says that it is fighting back with new technology, including an infra-red beam trap, and with the use of carbon dioxide.

It is estimated that there are now as many as 80 million rats in Britain.