Climate and monthly weather forecast
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.

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 211mm (8.31") 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 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.

Spring in Sri Lanka, characterized by March to May, witnesses steadily rising temperatures. By May, the thermometer can often register between 32.2°C (90°F) to 35°C (95°F). This period marks the transition from the dry season to the onset of the southwest monsoon. While the early spring months remain relatively dry, by late spring, especially in May, the southwestern parts of the country start experiencing the initial showers of the monsoon.

From June to August, Sri Lanka is gripped by the southwest monsoon. The weather becomes considerably wetter, especially in the southwestern region, receiving heavy rainfall. During this season, windward mountain slopes can record up to 2540mm (100") of rainfall, while the leeward eastern side remains comparably dry. The relative humidity is at its peak, creating muggy and often uncomfortable conditions.

September to November constitutes Sri Lanka's autumn. The southwest monsoon starts to recede in September, resulting in reduced rainfall. However, by November, the northeast monsoon begins, bringing moisture from the Bay of Bengal. This means that while the southwestern parts experience a decrease in rainfall, the northeastern slopes can get up to 1270mm (50") of precipitation during the onset of this monsoon.

The winter months, December to February, offer a respite from the intense heat and humidity. Temperatures during January oscillate between a pleasant 18.3°C (64.9°F) to 23.9°C (75°F). The central highlands, particularly Nuwara Eliya, experience cooler temperatures, ranging from 8.9°C (48°F) to 21.1°C (70°F) throughout this season. While frost is a possibility in the high mountains, most regions enjoy sunny days and milder temperatures, making it an attractive period for tourists.

January is one of the more favorable months for visiting Sri Lanka due to its temperate climate. Across the island, temperatures typically range from 18.3°C (64.9°F) to 23.9°C (75°F). However, notable cities such as Nuwara Eliya, located in the central highlands at an altitude of 1900 meters, experience cooler climes with temperatures between 8.9°C (48°F) and 21.1°C (70°F). In terms of extremes, January sits on the milder end of the spectrum, especially when compared to the sizzling heat of April and May, which are the hottest months of the year. Weather in January »

February in Sri Lanka continues the trend of pleasant conditions established in January. Temperatures across the country usually fluctuate between 18.5°C (65.3°F) to 24.5°C (76.1°F), maintaining a comfortable warmth. However, distinct climate variations are observed in specific cities. Weather in February »

March heralds a noticeable transition in Sri Lanka's weather patterns as temperatures begin to climb. Countrywide, average temperatures tend to hover between 19°C (66.2°F) to 25.5°C (77.9°F). However, as seen in preceding months, certain areas, such as Nuwara Eliya in the central highlands, experience a more temperate climate. Weather in March »

April stands out as one of the warmest months in Sri Lanka's annual climatic calendar. The nation experiences temperatures typically varying between 20°C (68°F) to 26.5°C (79.7°F). However, it's crucial to note the cooler exceptions like Nuwara Eliya. Weather in April »

May in Sri Lanka is characterized by a combination of persistent warmth and the commencement of the southwest monsoon. The country’s temperature readings, on average, span from 20.5°C (68.9°F) to 27°C (80.6°F). However, in elevated regions such as Nuwara Eliya, the thermometer indicates cooler conditions, typically between 10.5°C (50.9°F) and 23.5°C (74.3°F). The warmth of May matches that of April, confirming its status as one of the year's hottest months. Weather in May »

June in Sri Lanka is dominated by the continued influence of the southwest monsoon, ensuring consistent rainfall in several parts of the country. The average temperature generally oscillates between 20°C (68°F) to 26.5°C (79.7°F). Weather in June »

July signals the gradual easing of the southwest monsoon's grip over Sri Lanka, though the weather remains influenced by its patterns. The country observes average temperatures ranging from 20°C (68°F) to 26°C (78.8°F). The central highlands, with towns like Nuwara Eliya, persist in maintaining a cooler climate, where temperatures vary between 10°C (50°F) and 22.5°C (72.5°F). As the month progresses, there's a perceptible reduction in rainfall, especially when compared to the preceding months of May and June. Weather in July »

August in Sri Lanka represents a transition period where the southwest monsoon's influence wanes, giving way to clearer skies and drier conditions. Average temperatures during this month hover between 20°C (68°F) to 26°C (78.8°F). Weather in August »

September in Sri Lanka is predominantly marked by dry and warm conditions, serving as a brief respite between the two main monsoon seasons. Temperatures during this month generally lie between 20°C (68°F) to 26°C (78.8°F). Weather in September »

October in Sri Lanka serves as a precursor to the northeast monsoon, bringing about noticeable changes in weather patterns, especially in the northern and eastern parts of the island. Average temperatures in this transitional month span from 20°C (68°F) to 27°C (80.6°F). Weather in October »

November in Sri Lanka is characterized by the intensification of the northeast monsoon, which predominantly affects the northern and eastern sectors of the island. Across the country, average temperatures are consistent, ranging from 20°C (68°F) to 27°C (80.6°F). Weather in November »

In Sri Lanka, December is deeply entrenched in the northeast monsoon, a period predominantly influencing the northern and eastern portions of the island. Across the diverse terrains, temperatures moderately vary, generally oscillating between 20°C (68°F) and 28°C (82.4°F). Weather in December »