🇱🇰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, with a 1,340 km coastline. 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 monsoon (May–September) and the northeast monsoon (November–February) — tropical rainforest (Af) blankets the wet southwestern lowlands and central highland around Colombo, Galle, Kandy, and Nuwara Eliya, tropical monsoon (Am) characterizes the central east coast, tropical savanna (Aw) covers the dry northern and eastern lowlands including Anuradhapura, Trincomalee, and Hambantota, and a subtropical highland (Cfb) climate prevails on the highest plateaus.

Colombo on the southwest coast averages 26°C in January and 28°C in May with 2,400 mm rainfall almost evenly split between the southwest monsoon and inter-monsoon periods. Galle in the deep south registers 25°C in January and 27°C in May with 2,100 mm. Kandy in the central highlands averages 22°C in January and 25°C in May with 2,100 mm. Nuwara Eliya at 1,890 m records 14°C in January and 16°C in May with 1,930 mm — the country's coolest city.

Jaffna in the dry north averages 26°C in January and 30°C in May with 1,070 mm — rainfall peaking during the northeast monsoon from October to January. Trincomalee registers 26°C in January and 31°C in May with 1,640 mm. Hambantota in the deep southeast dry zone averages 26°C in January and 30°C in May with 1,070 mm. Pidurutalagala summit averages 9°C in January and 11°C in May with 2,100 mm and persistent cloud forest.

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. 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 has experienced intensifying multi-year droughts since 2017. Coral bleaching has affected the Hikkaduwa reef in 1998, 2016, and 2023. Sea levels are rising, posing threats to coastal settlements at Negombo and Beruwala.

Our archive covers 11 Sri Lankan cities with daily ERA5 reanalysis data going back to 1940. The warmest July averages occur in Trincomalee, around 32.6°C, while Kandy records the coldest January nights 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.