The exceptional heatwave that gripped the United Kingdom in late June cost the economy an estimated £1.15 billion ($1.54 billion) in lost output in a single week, according to a survey by the Grantham Research Institute at the London School of Economics and the Euro-Mediterranean Center on Climate Change. The study, based on a nationally representative sample of 1,950 adults, found that workers reduced their hours by an average of 0.47 hours during the week of 22 June, with 3.6 percent of respondents—equivalent to roughly 1.25 million workers—not working at all because of the heat. The total loss of 24 million working hours fell disproportionately on physically demanding sectors such as construction and agriculture, where exposure to high temperatures is greatest.

The heatwave, the second of three to strike Western Europe in as many months, was driven by a persistent high-pressure ‘heat dome’ that trapped warm air over the region. England recorded its hottest June since 1884, with a provisional high of 37.7°C in Norfolk, and the country experienced its first year in which temperatures reached 35°C in May, June and July. The Met Office confirmed that the last four years are all among the five warmest in UK history, with 2025 the hottest on record. A large majority—87 percent—of surveyed workers reported at least one health impact, including disrupted sleep, fatigue, dizziness and accelerated heart rate. Overnight temperatures set a new UK record of 23.5°C in Cardiff, preventing green spaces and buildings from cooling.

Viewed from continental Europe, the economic damage extended well beyond Britain. The same heatwave caused over 2,000 excess deaths in France and, according to the Energy and Climate Intelligence Unit, destroyed €2 billion worth of grain crops across the continent. In Germany, agricultural cooperatives cut their 2026 grain harvest forecast by 5.6 percent. Scientists from the World Weather Attribution group calculate that such extreme temperatures increase the probability of drought eighty-fold by accelerating soil moisture evaporation, threatening river levels, nuclear power plant cooling and key shipping routes, with knock-on effects for food prices and inflation.

Britain’s infrastructure and housing stock, designed for a cooler climate, remain poorly adapted. Only 49 percent of workers had access to air conditioning, and 27 percent said their employers made changes such as installing cooling or increasing ventilation. Elizabeth Robinson, director of the Grantham Institute, described the UK as “woefully under-adapted” and called on the government to make workplaces safer. The Met Office’s climate information scientist, Mike Kendon, noted that “what we used to think of as extreme, we increasingly consider as normal,” adding that the evidence shows “the climate of the 20th century has now gone.”

Meteorologists are monitoring a building high-pressure system that could deliver another heatwave in early August. With only 13 percent of rivers at normal seasonal levels and hosepipe bans already affecting over 20 million customers, the National Drought Group warns that many parts of England face a heightened risk of drought. The next milestone will be the Met Office’s updated seasonal outlook and any government response to calls for mandatory workplace heat standards.