🇱🇰Sri Lanka

Sri Lanka spans 5°55′–9°51′N as a tropical island country (approximately 65,610 km²) in the Indian Ocean separated from southern India by the narrow Palk Strait. The landscape is dominated by a low northern and coastal plain around Jaffna and Mannar in the dry zone, and a rugged central highland that rises to Pidurutalagala at 2,524 m, the country's highest peak.

This extraordinary topography produces a strong climate gradient driven by the central highlands intercepting both the southwest and the northeast monsoons: tropical rainforest (Af) blankets the wet southwestern lowlands and central hills around Colombo, Galle, and Kandy, tropical monsoon (Am) characterizes the central east coast, tropical savanna (Aw/As) covers the dry northern and eastern lowlands including Anuradhapura, Trincomalee, and Hambantota, and a subtropical highland (Cfb) climate prevails on the highest plateaus around Nuwara Eliya.

Colombo on the southwest coast sees highs of about 31°C in January and 32°C in May, with nights of 23°C and 26°C, and 2,400 mm rainfall almost evenly split between the southwest monsoon and inter-monsoon periods. Galle in the deep south sees highs of 30°C in January and May, with nights of 23°C and 26°C, and 2,350 mm. Kandy in the central highlands sees highs of 29°C in January and 30°C in May, with nights of 19°C and 22°C, and 1,840 mm. Nuwara Eliya at 1,868 m sees highs of 20°C in January and 22°C in May, with nights of 10°C and 13°C, and 1,840 mm, the country's coolest city.

Jaffna in the dry north sees highs of 29°C in January and 33°C in May, with nights of 22°C and 28°C, and 1,370 mm, rainfall peaking during the northeast monsoon from October to December. Trincomalee sees highs of 29°C in January and 35°C in May, with nights of 24°C and 26°C, and 1,640 mm. Hambantota in the deep southeast dry zone sees highs of 31°C in January and May, with nights of 23°C and 26°C, and 1,070 mm. Pidurutalagala summit is cooler still.

Major meteorological and environmental events affecting Sri Lanka include the Indian Ocean tsunami of 26 December 2004, which claimed the lives of over 35,000 people, and Cyclone Ditwah in November 2025, whose floods and landslides killed more than 600 people. Southwest monsoon flooding has caused recurring damage, including notable events such as the Kelani River floods of 2016 and the Galle floods of May–June 2017. The May 2003 Ratnapura landslides resulted in significant casualties. The dry zone experiences recurrent droughts. Coral reefs such as Hikkaduwa's are vulnerable to bleaching. Sea levels are rising, posing threats to coastal settlements.

Our archive covers 11 Sri Lankan cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Trincomalee, with average highs around 32.6°C, while Kandy has the coldest January nights, with average lows near 19.6°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.2°C.