🇻🇳Vietnam

Vietnam (331,212 km²) extends 1,650 km along the eastern Indochina Peninsula from 8°30'–23°22'N, spanning two principal climate zones: humid subtropical (Cwa) in the north with distinct seasons and tropical savanna (Aw) in the south with year-round warmth.

The northern highlands including Sapa experience cool winters with January highs near 12°C, nights around 6°C and occasional frost above 1,500 m elevation, while Hanoi (21°N) exhibits four seasons with hot, humid summers peaking at 32–35°C in June–August and cooler winters with January highs around 20°C and nights near 14°C, with occasional cold surges from Siberian high pressure.

The narrow central coast from Đà Nẵng to Nha Trang receives most of its rainfall during the northeast monsoon (September–December) with annual totals of about 1,400–2,200 mm, while the south experiences the southwest monsoon from May–October delivering 1,800–2,200 mm annually to the Mekong Delta.

The Trường Sơn (Annamite) Mountains create pronounced rain shadows and altitudinal gradients, with peaks exceeding 2,500 m supporting montane and cloud forests. Regional variation is extreme: northern coastal Móng Cái receives about 2,700 mm precipitation with typhoon exposure, the Red River Delta averages 1,600 mm concentrated in summer months, the Central Highlands plateau city of Đà Lạt at 1,500 m elevation maintains spring-like temperatures year-round with highs of about 21–25°C and nights of 12–16°C, while Ho Chi Minh City experiences minimal temperature variation with highs of 32–35°C and nights of 23–26°C year-round and distinct wet-dry seasons.

Typhoon Yagi (September 2024) struck northern Vietnam as one of the strongest storms in decades with sustained winds of about 160–180 km/h, killing more than 300 people and causing severe floods across the Red River basin, where the river at Hanoi reached its highest level in 20 years, while flash floods and landslides hit mountainous provinces.

The April–May 2024 Southeast Asian heatwave brought record-breaking temperatures to several countries in the region, with 39–40°C across northwestern and central Vietnam and southern Vietnam's longest heat wave in 30 years. Central Vietnam experienced severe flooding in October–November 2020 when a succession of tropical storms including Linfa, Molave, and Goni dropped over 3,000 mm of rain in places within weeks, killing about 190 people, displacing hundreds of thousands, and submerging cities like Huế. The 2016 Mekong Delta drought marked a major water crisis when El Niño-driven drought allowed saltwater intrusion more than 90 km inland.

Our archive covers 142 Vietnamese cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Hoàng Mai, with average highs around 34.7°C, while Lạng Sơn has the coldest January nights, with average lows near 11°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.2°C.