Wharfers will be shedding their jackets and donning their shades as east London prepares for the warmest day of the year today.

Temperatures could climb to about 20C by late afternoon rising from 15C at lunchtime – only a fraction cooler than parts of the country which are expected to reach 22C.

The morning has begun with a haze which will linger all day, taking the edge off the sun’s blast and the brief glimpse of spring will be shortlived. According to forecasters, there will be a noticeable southerly breeze by the end of the day preparing the way for showery outbreaks in the early part of Saturday.

“But it’s not that it’s going to be particularly cold,” said Met Office meteorologist Charles Powell. “It’s just returning to nearer normal after a week of temperatures being above average, so it will feel slightly colder.”

A week of balmy weather has had a sting in the tale – pollen levels have risen to moderate with people beginning to suffer hay fever.

Andrew Williams, nurse consultant at Homerton Hospital, east London, said: “People have already been coming in with symptoms triggered by the London plane trees.

“Now we are seeing high birch pollen levels, a lot of sufferers are presenting slightly earlier than usual as the problem gets worse.”

Air pollution will be elevated too with a mix of pollutants from the continent and Saharan dust although the problem should be eased by Atlantic winds.