Part of London hit 34.8C on Monday, breaking the UK’s all-time highest May temperature and setting a new benchmark for a bank holiday Monday. The reading was taken at Kew Gardens, and it also passed the previous hottest bank holiday Monday record of 33.3C, set on the August bank holiday in 2019.
Wales also logged its hottest May day, with 32.2C at Hawarden Airport in Flintshire, as forecasters warned parts of England could reach 35C on Tuesday. The Met Office said the heat would be exceptional in the UK even in mid-summer, let alone in May.
The latest burst of heat has arrived with the country already under pressure. The UK Health Security Agency issued its first amber-heat health alert of 2026 on Friday, covering much of England, including the West Midlands, East Midlands, East of England, South East and London. Yellow alerts were in place for the North East, North West, South West, and Yorkshire and Humber. Both alerts were due to remain active until 17:00 BST Wednesday.
The temperature surge also brought disruption beyond the thermometer. Around 500 properties in Sussex and Kent were left without water or had intermittent supply on Monday afternoon after demand jumped. South East Water said it was working as quickly and safely as possible to resolve the problem, while a number of bank holiday events across the UK were cancelled because of the extreme heat.
One of those cancellations came in Surrey, where Leatherhead Lions Club said its annual bank holiday donkey derby would no longer include the donkeys or a dog show, citing the welfare and comfort of the animals. The decision underscored how fast the heat wave has moved from a weather story into a public-safety and logistics problem, with outdoor plans, transport and water systems all feeling the strain at once.
The scale of the records points to how unusual this spell is. The UK recorded its warmest May night on Sunday, with highs of 19.4C in London, and more than half of the monthly record highs, seven out of 12, have been set since 2003. The Met Office linked the heat to warmth building under an area of high pressure near the UK, and said Scotland and Northern Ireland also recorded their highest temperatures for 2026 so far on Monday.
For now, the immediate question is not whether this is already a record-breaking spell. It is how much higher the temperatures go before the heat alerts expire on Wednesday evening, and how much more pressure follows on water, health services and the events that were supposed to take place under a bank holiday sky.
