🇮🇷Iran

Iran spans 25°03′–39°47′N, a large Western and Central Asian country covering approximately 1,648,195 km² bordering the Caspian Sea in the north and the Persian Gulf and Gulf of Oman in the south. The landscape is dominated by the great central Iranian Plateau ringed by mountain barriers including the Zagros chain along the southwest reaching above 4,200 m at Zard-Kuh, the Alborz along the Caspian shore crowned by Mount Damavand at 5,610 m (the country's highest peak and the highest volcano in Asia), and the Kopet Dag in the northeast.

The central plateau hosts the vast Dasht-e Kavir and Dasht-e Lut deserts, with the Lut routinely recording the world's hottest land surface temperatures. This topography produces an extraordinary climate range from humid subtropical (Köppen Cfa) on the Caspian shore to hot-summer Mediterranean (Csa) on the western Zagros foothills, hot and cold semi-arid (BSh, BSk) and desert (BWh, BWk) climates across the plateau interior, and colder mountain climates on the Alborz heights, with glaciers on the upper slopes of Damavand.

Tehran sees January highs of 9°C with nights of 1°C and July highs of 37°C, with 240 mm rainfall concentrated November–April. Mashhad sees January highs of 9°C with nights of −2°C and July highs of 35°C, with 250 mm; Esfahan January highs of 10°C with nights of −3°C and July highs of 38°C, with 190 mm. Ahvaz sees January highs of 18°C and July highs of 47°C with 220 mm, one of the world's hottest cities, reaching 53.7°C in June 2017. Bandar Abbas (Persian Gulf) sees January highs of 23°C and July highs of 38°C with 170 mm; Rasht (Caspian coast) January highs of 12°C and July highs of about 31°C with 1,380 mm.

Tabriz sees January highs of 4°C with nights of −5°C and July highs of 34°C, with 260 mm and snowy winters. Satellites have measured land surface temperatures in the Lut Desert above 70°C, with a peak of about 81°C. Major events include 2019 Golestan and Khuzestan floods, multi-year droughts (notably 1999–2001), summer heatwaves in Khuzestan, dust storms, Lake Urmia desiccation (~90% loss since 1990s), and Caspian sea-level variations.

Our archive covers 96 Iranian cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Shūshtar, with average highs around 46.7°C, while Shahr-e Kord has the coldest January nights, with average lows near −9.5°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 2.4°C.