A ferocious early-summer heatwave is tightening its grip across a vast arc from the Maghreb to the Arabian Peninsula, while also pushing into northern Europe, disrupting transport, closing schools and triggering a cascade of public-health alerts. In France, where the mercury is forecast to hit 40°C by Sunday or Monday, the national weather service has placed a quarter of the country under orange vigilance — the second-highest warning level. The state railway operator SNCF pre-emptively cancelled 71 regional trains linking Paris to the south, citing the risk of air-conditioning failures, and several municipalities, including Tours, have begun shuttering classrooms or curtailing the school day. Paris itself has taken the unusual step of officially permitting bathing in the Canal Saint-Martin to offer relief, a move the deputy mayor described as a pragmatic response to a situation where policing an informal swim “seemed somewhat absurd.”

Across the Mediterranean, North African and Gulf states are bracing for even more punishing conditions. Morocco’s meteorological directorate has issued an orange alert for a swath of provinces — from Errachidia to Boujdour — where temperatures are expected to oscillate between 40°C and 45°C from Friday through Sunday. Neighbouring Algeria faces a severe heatwave affecting ten wilayas, with coastal cities such as Algiers and Annaba forecast to reach 39–43°C, while inland areas like Relizane and Chlef could exceed 45°C. Civil protection authorities have urged citizens to avoid sun exposure, keep windows shuttered, and drink water regularly, reserving particular concern for the elderly, the chronically ill and children. In the Gulf, the UAE is recording its highest humidity levels of the summer so far, with coastal relative humidity reaching 90 per cent and internal temperatures climbing to 47°C. Lebanon, by contrast, is enjoying stable spring weather for now, but forecasters expect a marked rise in temperatures as summer officially begins next week, while Iran’s Ardabil province has been warned of a sharp spike on Saturday that could push highs to 39°C in northern counties.

British health authorities have also sounded the alarm. The UK Health Security Agency issued an amber heat-health alert from Thursday midday through Tuesday evening, covering the east, southeast and southwest of England, and the Midlands. Forecasters predict temperatures will climb to 32°C in East Anglia on Friday and reach 33°C in the southeast by Monday, accompanied by oppressive humidity that will make nights “quite uncomfortable for sleeping.” Officials are urging health and social care services to prepare for a “significant impact,” and reminding the public to look in on elderly relatives and neighbours. The NHS has reiterated classic heatwave guidance: stay out of the sun between 11am and 3pm, wear light clothing, avoid alcohol and caffeine, and use electric fans only if indoor temperatures remain below 35°C.

Viewed from Rome, where the health ministry has published ten rules for coping with extreme heat, the advice converges on a common set of precautions: avoid the hottest hours, drink at least a litre and a half of water daily, favour light meals rich in fruit and vegetables, and never leave children or vulnerable adults in parked cars. Italian officials also caution against directing mechanical fans straight onto the body, especially for bedridden elderly people, and note that air conditioning should be set no lower than 25–27°C to avoid thermal shock. These warnings are underpinned by a growing body of evidence that heatwaves are becoming more frequent and intense. Météo France records that of the 51 heatwaves registered since 1947, 34 have occurred since the year 2000 and 26 since 2011. With the summer solstice on Sunday extending daylight hours, and the built environment in many cities still poorly adapted to extreme heat, the coming days will test the resilience of public-health systems and infrastructure from the English Midlands to the Oued Ed-Dahab.