The national weather forecaster said in its last summer outlook in early May that there was a one in eight chance of Britain seeing the kind of temperatures experienced during the heatwaves of 2003 and 2006.
Although it thinks average temperatures across Britain could exceed those of last year and 2003, indications are that there will be less daily variations than during those periods, with more constant hot weather, a spokesman for the Met Office said on Wednesday.
"For the UK it is likely that exceptionally hot spells will be fewer than experienced in the summers of 2003 or 2006," the forecaster said in a statement.
"Predictions suggest that there is no more than a one in six chance that the UK summer 2007 overall will be as hot, or hotter, than 2003 or 2006."
The spokesman said that although the last publicly available Met Office prediction for an exceptionally warm summer was one in eight, at one point forecasters had thought there was a one in four probability. That figure was not made public.
The Met Office said current indications suggest drier than average weather in western-central Europe and a wetter than average summer in parts of northern Europe.
The latest summer forecast comes after temperatures dived into single figures in much of Britain over the weekend, with even a brief flurry of sleet at Canary Wharf in London on Tuesday afternoon.
Although the Met Office still compares average temperatures in Britain to the long-term average for 1971-2000, the benchmark is becoming increasingly irrelevant as the world warms up.
Since the mid 1980s the average UK surface air temperature has warmed by about one degree Celsius -- about twice the global warming trend averaged over all land areas.
The last summer which was colder than the 1971-2000 average was 1998, while the likelihood of exceptionally warm summers has increased, the forecasters said.
