🇻🇳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/Cfa) in the north with distinct seasons and tropical monsoon (Am) in the south with year-round warmth.

The northern highlands including Sapa experience cool winters with January averages 10–15°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 dropping to 13–17°C in January with occasional cold surges from Siberian high pressure.

The narrow central coast from Đà Nẵng to Nha Trang receives exceptional rainfall during the northeast monsoon (September–February) with annual totals exceeding 3,000 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 3,000 m supporting montane and cloud forests. Regional variation is extreme: northern coastal Móng Cái receives 2,800 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 averaging 18–22°C, while Ho Chi Minh City experiences minimal temperature variation with 26–28°C year-round and distinct wet-dry seasons.

Typhoon Yagi (September 2024) struck northern Vietnam as the strongest storm in decades with sustained winds exceeding 200 km/h, killing approximately 300 people and causing severe floods across the Red River basin including Hanoi, submerging rice paddies and triggering landslides in mountainous provinces.

The April–May 2024 Southeast Asian heatwave set temperature records across Indochina, with Đông Hà reaching Vietnam's national record of 44.0°C, causing health emergencies and agricultural losses. Central Vietnam experienced severe flooding in October–November 2020 when four successive typhoons including Linfa, Molave, and Goni dropped over 3,000 mm of rain in weeks, killing 200+ people, displacing hundreds of thousands, and submerging cities like Hội An and Huế. The 2016 Mekong Delta drought marked a major water crisis when El Niño combined with upstream dam operations reduced river flows to historic lows, allowing saltwater intrusion 90 km inland and severe rice production.

Our archive covers 142 Vietnamese cities with daily ERA5 reanalysis data going back to 1940. The warmest July averages occur in Hoàng Mai, around 34.7°C, while Lạng Sơn records the coldest January nights near 11°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.2°C.0°C national record.