A late-May heat dome anchored over western Europe pushed the United Kingdom to a provisional 35.1C at Kew Gardens in southwest London on Thursday afternoon, the hottest May day in temperature records dating back to 1860, the Met Office said. Monday's reading of 34.8C, also at Kew, had held the previous record for less than forty-eight hours. Amber heat-health alerts extended from the South West through London, the Midlands and East Anglia until five o'clock on Thursday evening.
The thermodynamic plume extends from Iberia across France, the Low Countries, the UK, Ireland and into western Germany. Saarland in southwestern Germany recorded the event's peak so far at 39.2C earlier in the week; more than twenty French towns broke May records on Monday, and France 24 reported daily highs continuing to climb on Thursday across the Loire valley. The whole-continent anomaly is twelve to sixteen degrees Celsius above the long-term climatological norm, according to data tracker IndexBox.
British infrastructure is showing strain. South Western Railway imposed speed restrictions on a third of its network on Thursday after track-defect reports trebled in twenty-four hours, with rails recording surface temperatures above sixty degrees in Surrey and Hampshire. Thames Water said roughly eighteen thousand properties across Kent had suffered water supply disruption since Wednesday, with the utility pledging to deploy water bowsers to the worst-affected areas.
Health systems are also taking the load. NHS England activated its national heat plan and instructed all acute trusts to clear non-urgent admissions where possible and to expand cooling capacity in emergency departments. The UK Health Security Agency said excess-mortality modelling for the heatwave was running at roughly six hundred deaths attributable to the event so far, a figure expected to climb after the spike passes.
Attribution scientists were unusually quick to put their names to the event. Friederike Otto of Imperial College London told reporters that "this record-breaking heat has the fingerprints of climate change all over it," and World Weather Attribution said it would publish a full peer-reviewed analysis next week. The World Meteorological Organization separately reported on Thursday that there is now a seventy-five per cent probability the global mean for 2026 through 2030 will exceed 1.5C above the pre-industrial baseline.
In France, the worst impacts have so far been in the south. Twenty-two departments are under canicule rouge, the highest national heatwave alert, and the agriculture ministry said early-stage damage to wheat and rapeseed crops in the Beauce was likely to reduce 2026 yields by between four and seven per cent. Energy regulator RTE flagged "tight" grid conditions for Thursday evening and Friday morning peak as French nuclear units throttled output for cooling-water constraints.
Iberia and Ireland saw their own records fall earlier in the week. Spain's Aemet logged a 41.5C reading in Sevilla on Monday, the earliest Spanish forty-one-degree reading on record. Met Éireann said Tuesday's 29.7C at Phoenix Park was Ireland's hottest day in May since records began, surpassing a 1944 marker. Heat dome modelling suggests the ridge will weaken from the western Atlantic side on Friday evening, with cooler Atlantic air pushing in over Ireland and southwestern England first.