High risk: Revellers defy safety warnings to jump off Magdalen Bridge into the River Cherwell in OxfordHolidaymakers were facing disruption on roads and rail plus a downturn in the weather as they made their getaway for the Bank Holiday weekend.
The weather and traffic warnings came as student revellers defied safety fears by jumping from a bridge in Oxford during high-spirited May Day celebrations there.
Cold winds are bringing in rain across much of the country, driving temperatures downwards after the recent hot weather.
The BBC's Peter Gibbs said: 'Temperatures are on a definite downward trend as we go through into this weekend dropping away by a good ten degrees in many places and we will see the return of night-time frost along with some cold winds blowing in from the north-east by day.'
Today will see heavy rain, with temperatures rising no higher than 16C (61F), with lows of 7C (41F). Heavy rain will continue tomorrow, but a strong north wind will drive temperatures down to a maximum of 12C (54F). The wind and 12C highs will persist on Bank Holiday Monday, even though rain should have tailed off by then.
Wales of a time: Miss Wales - 22-year-old hospital nurse Lucy Whitehouse - makes the best of the weather at her local beach at Barry Island on the south coast of WalesThe change in the weather follows an unseasonably warm April - the third sunniest for a century. It has produced a bumper crop of strawberries, according to industry body British Summer Fruits - with the berries not only arriving early but also proving tastier.
However, millions of hayfever sufferers face runny noses and breathing problems due to the high levels of birch pollen the weather has produced.
Today motorists were warned to expect traffic jams as shoppers descend on DIY superstores and garden centres to snap up holiday bargains.
Defiant: Students ignore the huge warning signs as they hurl themselves into the riverIn Manchester drivers were warned of 'significant delays' as hundreds of motorcyclists gather for a 'May-Hem' protest against soaring petrol prices.
Rail travellers are having to deal with delays and diversions as all major railway companies use to long weekend to carry out engineering work.
Network Rail warned rail travellers to plan their journeys in advance, with several tracks closed for the entire three-day weekend as part of its £35billion, five-year investment programme.
The National Rail website lists service changes for 23 of the UK's 28 rail companies on at least one of the three days.
Wet weekend: This jumper ditched most of his clothes for the dangerous stuntTrains will be diverted between Swindon and Bristol and between Rugby and Birmingham, while work will affect some services out of Liverpool Street in London and on the capital's Thameslink service.
The London Underground is also undergoing major work on nine of its lines, with the Jubilee Line closed for the entire long weekend.
The weather and traffic warnings came as student revellers defied safety fears by jumping from a bridge in Oxford during high-spirited May Day celebrations there.
Jumpers leapt from historic Magdalen Bridge into the shallow waters of the River Cherwell in Oxford as dawn broke.
Drenched: Caroline Stephenson's white top clings to her body as she walks with fellow jumper Megan Beardsley away from the riverJumping off the bridge on May 1 has become a custom almost as predictable as the Latin Mass sung by choristers at daybreak from the top of the tower of nearby Magdalen College.
Believed to have started in the 1970s, the habit is actively discouraged following a spate of injuries as students hit the bottom of the shallow stream.
About 40 people were hurt during the celebrations in 2005, with some of them taken to hospital.
Thames Valley Police said it was deploying extra officers to prevent disorder breaking out with more than 30 premises extending their licences for the day.
The Magdalen Choir sings every year as dawn breaks on May Day from the college's Great Tower in a tradition dating back to 1509.
source: dailymail