There has been almost no rain in England for the last three weeks, while many rivers in the north and West Midlands are notably or exceptionally low, new figures show.
Less than one millimetre has fallen in the South East and North East since May 31, with the rest of England seeing no rain at all.
The rivers Mersey, Weaver, Derwent, Till and the Upper Severn are all running at exceptionally low levels.
Most rivers across the south are normal, with the Itchen and Kennet exceptionally high.
The Environment Agency said river levels had decreased this week across all of the sites it monitors, while rainfall in May was 43% of the long term average for north-west England and 86% in the east.
Craig Snell, of the Met Office, said: “This time of year it’s not rare to have a prolonged dry spell. Go back to last year, when we had that unprecedented heatwave in July, parts of the south barely had a drop of rain for that entire month, parts of London only registered a millimetre of rain.
“That can happen when high pressure decides to settle itself across the UK, that keeps us dry, and that’s what we’ve seen for the last month or so.
“A this point in the month, rainfall amounts should be about 20% of the average and at the moment, most of us have hardly had a drop. So we are below par.”
Over the spring, there has been a sharp difference between the north and south of the UK, with Scotland experiencing below average rainfall and southern England above.
Cloud and rain is expected over the weekend and the Met Office has issued a yellow warning for thunderstorms on Saturday across Wales, the West Midlands and parts of the south between Bath and London.
Mr Snell said: “Next couple of days, we will see some some thunderstorms develop, they can be hit or miss. Some places very locally will quickly see their averages for June shoot up, but the measurement for the country as a whole, it will make a small dent because there’ll be very localised showers.
“I’d say 95% of people will probably be dry, 5% of the people will be very wet. So you balance that out and the vast majority of the UK is still dry.
“So we will see some slightly wet weather in next couple of days but then going into next week it looks like it will remain dry.
“It’s obviously not useful for some people. Farmers and growers like steady rain rather than heavy rain and then nothing.
“But then obviously it’s good news for holiday makers because you can do a little bit more in dry weather than you can in wet weather.”