Overnight temperatures in the continental U.S. were hotter in July than any other month in the 128 years on record, exacerbating the danger of the extreme heat that broiled large swaths of the country during the day. NOAA, which released the data Friday, found nationwide overnight temperature averages were more than 3° F (1.7°C) hotter than the 20th century average. Nighttime temperatures are warming faster than daytime highs as climate change, caused by the extraction and combustion of fossil fuels, drives up global temperatures overall — they are also more dangerous to human health because they rob the body of a chance to cool off. The month was also the planet’s sixth hottest July on record and skyrocketed electricity demand resulted in enormous amounts of fossil fuel air pollution. Though less reliant on precision measurements, boulders along rivers known as “hunger stones” revealed by extremely low water levels across Europe are no less ominous warnings that drought leads to hunger. “Wenn du mich seehst, dann weine,” or, “If you see me, weep,” one inscription made in 1616 on a boulder in the Elbe River warns. The current European drought is on course to be the worst in 500 years. (July overnight heat: AP, Washington Post $; 6th hottest July: Yale Climate Connections; Air pollution: Boston Globe $; Hunger stones: McClatchy, via Miami Herald $, Sacramento Bee $; European drought: The Guardian, TIME, Climate Signals background: Hot nights (graph), Drought)