On the morning of Sunday, 19 July 2026, residents of South and East Jakarta stepped outside to find the sky had turned blurry and opaque. The Indonesian meteorological agency, BMKG, had a term for it: udara kabur, a haze that reduced visibility and gave the city’s familiar skyline a muted, watercolour wash. It was not storm or smoke, but a stillness that trapped the heat; by mid-morning, temperatures had already climbed past 28°C, and the forecast promised a day of thick cloud and intermittent sun — cerah berawan — across the capital. In Kepulauan Seribu, the Thousand Islands just offshore, the sky was merely overcast, but for millions in the metropolis, the haze was a quiet, disorienting presence.

Half a world away, Iran was bracing for something far more searing. In Khuzestan province, the national weather service issued its highest-level red warning for “unusual heat”, forecasting temperatures of 49.5°C and above in cities like Ahvaz, Omidiyeh and Mahshahr. The subtropical high pressure system squatting over the country had turned the air into a heavy, stagnant blanket. Mohammad Asghari, a meteorologist, advised farmers across a dozen provinces to spray pesticides only in the early morning, before the afternoon winds scattered the chemicals uselessly. In Ilam, orchard owners were told to irrigate at night to ease the stress on trees. Across the central plateau — Yazd, Isfahan, Semnan and Qom — daytime highs hovered between 40 and 44°C, while strong winds and dust storms were forecast for the east and southeast. Iranian meteorological models showed no sign of a cooling system arriving before the end of the month, raising official concerns about water and electricity consumption and prolonging thermal stress along the humid northern Gulf coast.

In Spain, the State Meteorological Agency (Aemet) warned that a new extreme heatwave would begin on Tuesday 21 July, potentially the third of the summer. A cut-off low pressure system (DANA) to the west of the Iberian Peninsula, coupled with an anticyclone over North Africa, was expected to pump a mass of hot, dry, dust-laden air across the country and the Balearics. Forecasters predicted that the Guadalquivir valley and the southeastern interior could see 44°C, with isolated points touching 45°C. The episode, linked to a cyclone that would reinforce the heat for at least 48 hours, was set to intensify through Wednesday, raising wildfire risk and health alarms. In the Ebro valley and the northeastern depressions, maximums of 39 to 41°C were expected, while the Genil basin would recurrently hit 40 to 42°C.

By the time the haze lifted over Jakarta in the evening, the city exhaled, but the memory of the opaque sky lingered — a quiet prelude to the scorching days unfolding elsewhere. In Spain, the countdown to the heatwave had begun; in Iran, the red alert remained in place. From a blurry dawn in Southeast Asia to the approaching furnace in southern Europe, the week revealed a planet where extreme heat was no longer an outlier but a recurring character in the story of summer.