THE mercury topped 20 degrees Celsius in North Herts last week, in what equalled the hottest March day for at least 40 years.

The thermometer hit 21.6 degrees on Wednesday, more than 10 degrees above the month average.

The temperature was recorded by met observer Richard Barker, who has been keeping records for 40 years. It is only the third time in the area it has gone over 20 degrees in March. It also equalled the hottest temperature he has ever recorded during that month - the other time was on March 17, 1990.

“It has been a remarkable spell. We’ve not had any rainfall recorded since the 18th, so we’ve also had a long spell without anything at all,” said Mr Barker.

February, March and April is the driest quarter of the year, but this month has been even drier than usual, added Mr Barker.

Combined with the driest year recorded in 2011, it is this that has contributed to the hosepipe ban, which will take effect this week.

“That’s what is the real problem here,” he said.

“We had a much less amount of rain than normal.

“Certainly in the next few days, it’s apparent there’s not going to be any significant rain, but things can change very quickly.

“It’s going to rain sooner or later.”

Monday, Tuesday, and Thursday of last week were also far warmer than usual. Temperatures recorded in North Herts on these days varied between 19 and 19.1 degrees Celsius.

But meteorologists predict that the weather will now cool down again, with rain and even snow a possibility.

Herts County Council has put out a warning, urging people to be careful, as low temperatures and icy conditions are predicted.

Rob Smith, transport management assistant director, said: “Overnight temperatures are expected to drop below zero from Tuesday night so we will continue to salt all the main routes around the county.

“Please take care if you’re out and about in the next few days. If you are driving, leave plenty of room between you and the vehicle in front, steer and brake very gently and reduce your overall speed. Pedestrians are also asked to take a great deal of care on pavements and when crossing the road.”