Laos
2 cities
Climate overview
Laos lies mostly between 14° and 23°N as a landlocked Southeast Asian country (approximately 236,800 km²) on the Indochinese peninsula bordering China, Vietnam, Cambodia, Thailand, and Myanmar, dominated by the Annamite Range running along the Vietnamese border (Phou Bia, about 2,820 m, the country's highest peak), the rugged northern highlands of Phongsali and Houaphanh, the southern Bolaven Plateau (a fertile coffee-growing volcanic upland), and the Mekong River valley along the Thai border (the country's spine, with Vientiane and Luang Prabang). The climate is monsoonal: tropical savanna (Aw) across the Mekong lowlands, wetter conditions on the eastern Annamite slopes, and a humid subtropical (Cwa) tendency at higher northern elevations.
Vientiane has January highs of 29°C with nights of 18°C and April highs of 35°C with 1,640 mm rainfall almost entirely from the southwest monsoon May–October, with the severe pre-monsoon hot season April–May when temperatures can reach 40°C. Luang Prabang records January highs of 28°C with nights of 15°C and April highs of 35°C with 1,470 mm. Pakse on the Bolaven margin has January highs of 32°C with nights of 19°C and April highs of 36°C with 2,030 mm.
Sam Neua in the high north sees January highs of 20°C with nights of 10°C and April highs of 29°C with 1,500 mm, among Laos's coolest cities. The Bolaven Plateau can receive over 3,000 mm. Major events include the severe July 2018 Xe-Pian Xe-Namnoy hydropower dam collapse during a tropical-storm-driven flood (71 deaths, displacing thousands), the record 2008 Mekong flood at Vientiane, the severe 2019 and 2020 droughts shrinking the lower Mekong, intensifying pre-monsoon heatwaves above 42°C (Laos set a national record of 43.5°C at Luang Prabang in May 2023), and upstream damming, including in China, worsening Mekong low flows.
Our archive covers 2 Lao cities with daily ERA5 reanalysis data going back to 1940. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.5°C.
How the climate has shifted in Laos
Average across 2 cities with full ERA5 coverage: 1940–1970 baseline vs the last decade (2016–2025).
- Annual mean temperature
- 25.6°C→27.1°C
- Days above 30°C per year
- 223 days→288 days+65
- Frost days per year
- 0 days→0 days+0
- Tropical nights (≥20°C) per year
- 259 nights→282 nights+23
What's unusual right now
From a snapshot of the world's largest cities updated each hour. Today's mean temperature compared with each city's long-term average for the same calendar date (ERA5 climatology, 1940 onward). Last 30 days uses each city's rolling daily-mean vs its monthly average. Not a global ranking.
Running warm
Warmer than usual