The torrential rain brought by ex-Hurricane Bertha caused the wettest day of the year, the Met Office said.
Huge rainfall totals and strong winds battered parts of the UK over the weekend, with severe conditions continuing in parts of Scotland today.
Fair Isle in Shetland saw 132.6 mm of rain between 10am on Saturday and 10am on Sunday, which is almost double the 70.3 mm full-month average for August.
This was the wettest 24-hour period of 2014 so far, despite it being in August when we would hope for dry, sunny conditions.
Lossiemouth in Moray was deluged with 100mm of rain during the same time, despite a full-month average of 61.9mm.
The conditions have caused severe problems in Scotland, where heavy and persistent rain flooded homes, while the transport network was disrupted in north-east Scotland.
Stormy conditions spread north overnight as driving rain and high winds swept through northern England and Scotland.
The Met Office issued a yellow weather warning for rain - which means "be aware" - covering large parts of Scotland today.
Strong winds have added to the problems, with gusts of 108mph measured on Cairngorm Summit at around 8am today.
The strongest winds recorded on non-mountain sites were 64mph at The Needles, Isle of Wight around midday yesterday and 62mph at the Tain Range, Ross and Cromarty at around 8am today.
A taxi passenger was injured in Hull when a tree crashed into a cab during a freak storm.
June Stephenson, 57, was in the back of a taxi waiting for her husband Martin to get in when a tree fell on to the vehicle during a sudden burst of extreme weather the couple said was "like a tornado".
Mrs Stephenson suffered minor injuries to her arms and face in the incident in Hopewell Road, which left a trail of uprooted trees, damaged roofs and flooding.
Mr Stephenson, 55, said: "We were going to meet my daughter for her anniversary. It was very windy but, as I locked the back door I could see there were some panels flying about and the sound of the wind changed.
"I came round the front to see the car was buried by the three trees.
"The wife was in the car and I didn't actually know what had happened."
Mr Stephenson said his wife went back to hospital today to have glass removed from her arm.
He said: "It had come and gone in a matter of 15 or 20 seconds. It was all over with.
"As she was getting in, just as she shut the door, the tree's actually come down on top of her, on top of the car."
The Scottish Environment Protection Agency (Sepa) issued 41 flood warnings, indicating flooding is expected, and seven flood alerts, where flooding is possible.
The Environment Agency issued 10 flood warnings and 37 flood alerts across England and Wales.
Marc Becker, Sepa's duty hydrology manager, said: "We are now seeing the larger rivers respond and further flooding impacts are anticipated in Huntly, Elgin and communities along the River Spey including Kingussie, Newtonmore, Aviemore, Aberlour, Rothes, Garmouth and Kingston. There is also the possibility of issues on the Dee, Don - including impacts to camp sites adjacent to these rivers - and Findhorn later today."
Met Office forecaster Charles Powell said: "There has been quite a lot of heavy rainfall in northern Scotland today.
"The rest of the UK has been left with a breezy day. We've had quite a few showers. Some of those have been heavy, but because of the strength of the wind they are moving through quite quickly.
"For August, it's relatively unseasonable in terms of the rain.
"The low pressure will stick around until at least tomorrow, if not Wednesday.
"We're going to have to wait until Thursday or Friday before we see something more settled. It's a slow, gradual improvement through the week."
Zoe and Wayne Ritchie said their home in Norland Avenue, Hull, was flooded for the second time in five weeks yesterday.
Mrs Ritchie said the water very quickly rose to kerb level.
"Within another five or 10 minutes it was down the garden and coming in, really quickly," she said.
The couple said the water level began to reduce within about 45 minutes of firefighters arriving with pumps.
But Mrs Ritchie said the flood has left a stinking mess in her home.
She said: "Knowing that this street floods quite a lot, something should have been done about these drains. Obviously they can't take the water. Every time it rains it tends to pool.
"At the end of the day it's people's homes, people's belongings and the upheaval. It's not fair."
In Scotland, motorists were warned to expect disruption and Transport Scotland - alongside its partners, including the local authorities, Sepa and Police Scotland - said it was monitoring the situation closely to ensure it was well prepared for the conditions.
Traffic Scotland operator manager Stein Connelly said drivers in parts of the North East and Highlands and Islands were likely to face difficult road conditions due to the rain.
He said: "We would advise people in these areas to prepare for some travel disruption and to allow extra time for their journeys. They should also check the relevant websites for up-to-date travel information."
Music festivals were cancelled and sporting contests had to be re-routed over the weekend.
The RideLondon Surrey Classic, which sees more than 20,000 cyclists pedal through rural Surrey before ending on the Mall, was shortened from 100 miles to 86 - missing out the challenging Box Hill climb - amid fears of heavy rain.
A performance by singer Katherine Jenkins which was due to close the Junction 16 festival at Betley Farm in Cheshire was called off.