Monthly weather forecast and climate
Sri Lanka

Flag of Sri Lanka
Flag of Sri Lanka

The climate of Sri Lanka

Sri Lanka is a tropical country with a year-round hot climate, moderated by oceanic winds. Two-thirds of the country made of the northern half and the southeastern quarter has a tropical wet and dry climate (Köppen climate classification Aw). The central highlands have a tropical monsoon climate (Köppen Am). The southwestern quarter has a tropical rainforest climate (Köppen Af), with an oceanic influence (Köppen Cfb) in small sections. Sri Lanka, an island country in South Asia, lies in the Indian Ocean. The Arabian Sea lies in the northwest and Bay of Bengal in the northeast. The Gulf of Mannar and the Palk Strait separates Sri Lanka from the Indian subcontinent. The tropical latitudes, the monsoon, and proximity to large bodies of water, chiefly influence the climate.

Sri Lanka lies between 5°N to 10°N, on the Indian Plate, in the Indian Ocean. The island is mainly flat, with low-lying coastal plains. Mountains rise only in the south-central part, but there are numerous rivers. Mahaweli River is the longest of the 16 principal rivers on the island, with a length of 208 miles. Bambarakanda Falls are the highest waterfalls at the height of 263 meters. Sri Lanka has a long coastline of 985 miles that supports marine ecosystems like fringing coral reefs and mangroves. The island has 45 estuaries and 40 lagoons. The mangrove ecosystem occupies over 7000 hectares and supports a diverse marine ecosystem. There are dozens of other off-shore islands, including the largest, Mannar Island. Adam’s Bridge is a former land connection to the Indian mainland, which is now mostly submerged. Pidurutalagala is the highest point at 2524 meters above sea level.

Summers are hot in Sri Lanka, followed by heavy rain in the monsoon season and mild winters. April and May are the hottest months, with average high temperatures in the 32.2°C (90°F) to 35°C (95°F) range. The average low temperatures in January range between a mild 18.3°C (64.9°F) to warm 23.9°C (75°F). Winters are pleasant with relatively less precipitation and ample sunshine. Nuwara Eliya, in the central highlands, at an altitude of 1900 meters, has cool temperatures between 8.9°C (48°F) and 21.1°C (70°F) throughout the year. Winter frost is likely in the high mountains, which receive the least sunshine. The average yearly temperature in Sri Lanka ranges between a warm 27.8°C (82°F) to 30°C (86°F). Temperatures vary from -13.9°C (7°F) to -11.1°C (12°F) between day and night and seasons. Microclimatic differences exist between the southwest, the central highlands, and the rest of the country.

Sri Lanka receives ample annual rainfall between 965.2mm (38") and 2540mm (100"). The northwest and the southeast are the driest, while the southwestern region is the wettest. The southwest monsoon runs from the last week of May to October. The mountains of the Central Highlands unload the moisture that the winds carry from the Indian Ocean. Windward mountain slopes in the southwest register up to 2540mm (100") of heavy rainfall, but leeward sides in the east receive little rain. The northeast monsoon from December to March brings moisture from the Bay of Bengal. The northeast mountain slopes receive up to 1270mm (50") during the northeast monsoon season. Sri Lanka receives abundant annual sunshine between 2500 hours and 2850 hours. The southeast and northwest regions receive the most sunshine in the country, while the mountainous regions in the interior register the least sunshine amid cloudy skies. The relative humidity is highest during the rainy season and lowest during the summer. The average seawater temperatures in Colombo remain in the warm 27.2°C (81°F) to 30°C (86°F) range.

The highest temperature on record in Colombo, the capital, is 40°C (104°F), while the record for the lowest temperature is 15.6°C (60.1°F).

The best time to visit Sri Lanka

The best time to visit Sri Lanka is from January to March, with comfortable temperatures between 21.1°C (70°F) to 31.1°C (88°F). The precipitation is relatively low in much of the country, except on the east coast. The retreating monsoon registers an impressive 210.8mm (8.3") in Batticaloa in January but tapers down by the end of the month. The winter season has pleasant conditions and is less humid than the rest of the year. Beach holidays are best from January to September in the northwest, east, and southeast coasts. The southwest coasts are delightful destinations between January and March. Tropical cyclones are rare during the winter.

The worst time to visit Sri Lanka

The worst time to visit Sri Lanka is from May to October during the rainy season. The humidity is at its peak, and the high heat index makes the conditions uncomfortable. The island receives heavy rainfall, and the possibility of rain is more than 50% every day. Rough seas make water activities challenging. Strong winds bring rubble and mess on the beaches. The rainy season is prone to thunderstorms, landslides, mudslides, and heavy rain. Tropical cyclones pose a significant threat along with tsunamis. The daily sunshine is at the lowest of the year due to the prevalent cloud cover.

Weather hazards

Sri Lanka faces weather hazards, such as floods, droughts, tropical cyclones, and tsunamis. Tropical cyclones usually form between May and November. Tropical depressions are possible throughout the year due to the proximity to the equator and warm seawaters. A tsunami brought a substantial loss of life and property in December 2004 in Sri Lanka. Recurrent flood events, which damage the infrastructure, are the result of an increase in the average rainfall in the country. Torrential rainfall brought landslides and floods, which resulted in a loss of life of 200 people in May 2017 and September 2019. The Global Climate Risk Index put Sri Lanka in the second position for the impact of extreme weather events in 2017.

Weather in January

January is pleasant in the mild winter of Sri Lanka, with short days and moderate sunshine. Colombo registers average temperatures in the warm 22.2°C (72°F) to 31.1°C (88°F) range and is less humid than the wet season. The southwest region records its lowest monthly precipitation of 61mm (2.4") to 76.2mm (3"), with the skies mostly clear for 42% of the time. Weather in January »

Weather in February

February is mild and the driest month in many places in Sri Lanka. Temperatures rise slightly to register between 22.8°C (73°F) to 30°C (86°F) in the northwest, with 9 hours of bright sunshine. The precipitation drops below 50.8mm (2") everywhere except the eastern coast where it is between 101.6mm (4") and 127mm (5"). Weather in February »

Weather in March

March sees a rise in temperatures in Sri Lanka at the end of the cold season. The bright daily sunshine of 9 hours keeps the skies clear for 60% of the time in most places. The average temperatures in Colombo are in the warm 23.9°C (75°F) to hot 32.2°C (90°F). The precipitation registers up to 127mm (5") in the southwest, but the beaches see relatively dry periods and have calm waters. Weather in March »

Weather in April

April is a hot and dry month in the summer of Sri Lanka, with 9 hours of bright sunshine. The average temperatures range between 26.1°C (79°F) to 32.8°C (91°F) in the northwest, interior, and eastern regions. Jaffna and Mannar are hot, while Puttalam and Kapatiliya further south see up to 175.3mm (6.9") of rainfall. Weather in April »

Weather in May

May is usually the hottest month of the year in Sri Lanka, with the average high temperatures in the 31.1°C (88°F) to 33.9°C (93°F) zone. The days are hot, but nights do not provide relief, with the humidity due to the impending monsoon. Weather in May »

Weather in June

June is hot, humid, and wet in Sri Lanka, as the southwest monsoon arrives in the country. The rainfall is heavy in the southwest region and registers between 177.8mm (7") to 228.6mm (9"), with at least 16 wet days in the month. The northwest region is relatively dry but cloudy and receives less than 38.1mm (1.5"). Weather in June »

Weather in July

July is a humid and wet month in Sri Lanka, with a marked decrease in precipitation. The average temperatures range between 27.8°C (82°F) to 31.7°C (89.1°F), with predominantly muggy conditions. The southwest region receives up to 63.5mm (2.5") of rain, while it is less than 38.1mm (1.5") in the other parts of the country. Weather in July »

Weather in August

August is a wet month in Sri Lanka, with ample rain amid generally humid conditions. The average temperatures are in the range of 27.8°C (82°F) to 31.1°C (88°F) in Jaffna, Mannar, and the northwestern region, which see than 30.5mm (1.2") of rainfall. Weather in August »

Weather in September

September is humid and wet in the rainy season in Sri Lanka. The average temperatures in the northwest are in the 27.2°C (81°F) to 31.1°C (88°F) range, while they scale between 26.7°C (80.1°F) to 33.9°C (93°F) in the southeast. Weather in September »

Weather in October

October is the second peak of the southwest monsoon in Sri Lanka. The southwest region receives heavy rainfall between 304.8mm (12") to 381mm (15"), and even the interior regions receive up to 254mm (10"). Mountainous regions in the central highlands receive torrential rainfall and remain mostly cloudy with hardly 2 hours of daily sunshine. Weather in October »

Weather in November

November sees the departure of the southwest monsoon in Sri Lanka but brings the northeast monsoon to the eastern region. The western region receives between 203.2mm (8") to 254mm (10") of precipitation during the transitional period. Weather in November »

Weather in December

December is a mild winter month in Sri Lanka, with moderate daily sunshine of 7 hours. The average temperatures in Jaffna are in the warm 25.6°C (78.1°F) to 28.3°C (82.9°F), while in Colombo they register between 23.3°C (73.9°F) to 30.6°C (87.1°F). Weather in December »
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