Record-breaking water temperatures at the Potomac River on July 4, 2026, are being linked to a localized fish kill in Maryland. The water temperatures reached a record high of 34.7°C (94.4°F) near Little Falls amid a record-breaking heatwave. Significant fish mortality was reported along a stretch of the river between White’s Ferry and Violette’s Lock soon after.
LaGuardia Airport recorded an official temperature of 34.4°C (94°F) around midnight into July 4, 2026, establishing the station’s highest midnight temperature on record as an intense heat wave affected New York City and much of the northeastern United States. According to National Weather Service observations, the reading surpassed the previous midnight record of 33.9°C (93°F) set on July 18, 2013. The National Weather Service maintained Extreme Heat Warnings across much of the New York metropolitan area as dangerous heat persisted through the overnight hours.
A dangerous heat wave continued to intensify across much of the central and eastern United States on Friday, July 3, 2026. Numerous daily temperature records have already broken and more are expected through the Fourth of July holiday weekend. The National Weather Service (NWS) warned of widespread Major to Extreme HeatRisk and heat index values reaching 46°C (115°F).
Hungary recorded its highest temperature since observations began on June 30, 2026, when the temperature reached 42°C (107.6°F) in Szécsény, surpassing the previous national record of 41.9°C (107.4°F) measured in Kiskunhalas in 2007. The same heat wave also established a new all-time temperature record in Budapest and rewrote numerous national and capital daily maximum and minimum temperature records between June 29 and July 1, according to HungaroMet.
Slovakia set a new national all-time temperature record of 41°C (105.8°F) at Turňa nad Bodvou on June 29, 2026, as a late-June heat wave brought record daytime and overnight warmth to the country. The minimum temperature at Bratislava–Koliba fell only to 26.3°C (79.3°F) on June 27, the highest June minimum recorded within the Slovak Hydrometeorological Institute (SHMÚ) network since 1951.
Germany provisionally recorded its highest air temperature on record on June 26, 2026 as an exceptional late-June heatwave continued to rewrite temperature records across Europe, prompting widespread red heat warnings, disrupting public life and raising concerns over growing impacts on health, infrastructure and ecosystems.
Temperatures reached 36.7°C (98.1°F) at Merryfield, Somerset, on June 25, 2026, provisionally making it the hottest June day on record in the United Kingdom, according to the UK Met Office. The agency also reported new provisional June records in Wales and record-equalling heat in Northern Ireland.
At least 40 people have drowned in France since June 18, 2026, while seeking relief from an exceptional heatwave that has pushed temperatures to record levels across much of the country.
Portugal set a new national May temperature record on May 27, 2026, after Mora reached 40.3°C (104.5°F) during an early-season heatwave, according to the Portuguese Institute for Sea and Atmosphere (IPMA). The reading surpassed the previous May extreme of 40°C (104°F), recorded at Pinhão on May 30, 1953, and matched at Termas de Monfortinho on May 30 and 31, 2001.
France recorded its hottest May day since records began on May 26, 2026, while temperatures climbed to 37.8 °C in southwestern parts of the country on May 28. Multiple stations across France set new all-time May temperature records this week as a prolonged heat dome pushed daytime temperatures into the upper 30s°C (upper 90s°F) and kept nighttime temperatures unusually high across much of the country.
