Highlights

Predictions: According to the US NOAA Climate Prediction Center, rainfall is expected to decrease across Sri Lanka during 16–22 June 2026. During this period, the Western Hills are forecast to receive between 55 and 85 mm of rainfall. From 17–23 June, winds are predicted to be predominantly from the southwest and west, with speeds ranging between 5 and 10 m/s.
 
ElNiño Event: As of mid-June, the NOAA Climate Prediction Center (CPC) has declared that the Pacific Ocean has transitioned into El Niño conditions. El Niño is a natural climate pattern that occurs when ocean waters in the central and eastern Pacific become warmer than usual, affecting weather patterns around the world. Currently, sea surface temperatures in the equatorial Pacific (Niño 3.4 region) are around 1.1°C above average. However, the Indian Ocean is currently behaving differently from what is typically expected during an El Niño event, with warmer-than-normal sea surface temperatures, enhanced rainfall activity, and unusual wind patterns.
 
Monitoring: Compared to May, which experienced nearly double the expected rainfall, relatively dry conditions were observed across Sri Lanka during 1–12 June 2026. Between 10–16 June, the average daily rainfall was 4 mm. The highest daily rainfall was recorded on 11 June, with 59 mm in Colombo and 48 mm in Ratmalana. During 8–14 June 2026, winds at an elevation of 1.5 km were predominantly from the west, with speeds ranging between 10 and 15 m/s. Overall, temperatures across Sri Lanka were typical for June. The Eastern Plains recorded an average maximum temperature of 35.2°C, while the Eastern Hills recorded an average minimum temperature of 19.4°C.
 

Rainfall Prediction: Rainfall is expected to decrease across Sri Lanka during 16–22 June compared to the previous week. The Western Plains are forecast to receive 55–85 mm of rainfall, while the Western Hills and Southern Plains are expected to receive 35–55 mm. The Northern Plains, Eastern Hills, and Eastern Plains are forecast to receive 15–35 mm of rainfall. During 23–29 June, rainfall is expected to decrease further. The Western Plains are forecast to receive 55–75 mm of rainfall, while the rest of Sri Lanka is expected to receive 5–25 mm.

Monitored Rainfall: Compared to May, which experienced nearly double the expected rainfall, relatively dry conditions were observed across Sri Lanka during 1–12 June 2026. During 10–16 June, the average daily rainfall was 4 mm. The highest daily rainfall during this period was recorded on 11 June, with 59 mm in Colombo and 48 mm in Ratmalana.

Monitored Land & Sea Temperature: During 10–16 June, the maximum average temperature across Sri Lanka was 32.0°C, slightly lower than the previous week (32.1°C). The Eastern Plains recorded the highest temperatures, reaching 35.2°C. Sea surface temperatures around Sri Lanka were above the seasonal average, ranging from +1.0°C to +1.5°C around the western and eastern coasts, and +0.25°C to +1.0°C around the northern and southern coasts.

 

Monitored & Predicted Wind: During 8–14 June 2026, winds at an elevation of 1.5 km were predominantly from the west, with speeds ranging between 10 and 15 m/s. From 17–23 June 2026, wind speeds are expected to decrease to 5–10 m/s, blowing from the southwest and west.



Terminology for Rainfall Ranges

TerminologyRainfall (mm/week)
Light ShowersLess than 12.5 mm
Light to ModerateBetween 12.5 mm and 25 mm
ModerateBetween 25 mm and 50 mm
Fairly HeavyBetween 50 mm and 100 mm
HeavyBetween 100 mm and 150 mm
Very HeavyMore than 150 mm