Thunderstorm warnings are in effect across much of the United Kingdom, with forecasters predicting up to 40mm of rainfall within hours in some areas. Yellow alerts, issued by the Met Office, cover Northern Ireland, Wales, southern Scotland, and most of England, with warnings of winds up to 45 mph. These conditions could disrupt driving, delay public transport, and cause flooding.

Despite the adverse weather, festival-goers have largely continued their celebrations over the bank holiday weekend. Attendees at London's Notting Hill Carnival shielded themselves from the rain with umbrellas and cardboard. The carnival is marking its 60th anniversary this year, with its main parade drawing larger crowds on Monday after a quieter start on Sunday with the traditional Panorama steelband competition.

Revellers at the Reading and Leeds Festivals donned ponchos and navigated muddy conditions. Some festival-goers were observed playing in puddles and mud, while others sought shelter.

Met Office meteorologist Kathryn Chalk advised that umbrellas would be necessary for many as showers move across the country. She noted the possibility of heavy, intense downpours, frequent lightning, thunder, and hail, particularly across the west in the afternoon. Showers are expected to become banded, bringing longer spells of rain to southern Scotland and northern England. Drier conditions with sunny spells are anticipated in the far south and east, though isolated showers remain possible.

Temperatures are forecast to be around 23C (73F) in Norwich, 22C (72F) in London and Hull, 21C (70F) in Cardiff, and 18C (64F) in Glasgow. Monday, a bank holiday for England, Wales, and Northern Ireland, is expected to have a largely dry afternoon with some scattered showers.

The inclement weather also impacted sporting events, with England's Test match against Pakistan at Lord's in London being halted by rain. Additionally, seven areas in England are under flood alerts from the Environment Agency, indicating a possibility of flooding.