Highlights

Monitoring

Sri Lanka experienced a relatively dry period from 19-24 Aug with daily average rainfall ranging from 0.2-5 mm. During 19-24 Aug, the average daily rainfall across SL was 1.5 mm. Highest daily rainfall was in Colombo – 33.8 mm on 24 Aug, Hambantota – 23.8 mm on 21 Aug & Galle – 16.1 mm on 23 Aug. August has the highest winds in SL generally, marking the beginning of the kite flying season. From 17-23 Aug 2026, winds at 1.5 km elevation were mostly from the Northwest & South West at speeds of 10 – 15 m/s. During 19-24 Aug, average maximum temp in SL was 32.4°C; Polonnaruwa was the warmest – 38.6°C.

Predictions

From 25 – 31 Aug, 45-55 mm of rainfall is predicted for the Eastern Plains; 25-45 mm of rainfall is predicted for the Western & Eastern Hills; 5-25 mm rainfall is predicted for Southern Plains; 0-5 mm rainfall is predicted for the Northern, Western & Eastern Plains. From 01-07 Sep, rainfall shall be similar to the previous week (Source: NOAA CPC), From 26 Aug–01 Sep 2026, winds are predicted to slow down to 8-12 m/s and arrive from the Northwest & Southwest.

El Niño Event

El Niño conditions continue to prevail across the equatorial Pacific Ocean (Niño 3.4 region). Currently, sea surface temperature in the Niño 3.4 region are around 2.7°C above average. Meanwhile, the Indian Ocean could be gradually transitioning towards a positive IOD phase, which is typically associated with El Niño. According to CCSR/IRI Multi-Model Probability Forecast, there is a 45% likelihood of Sri Lanka receiving higher-than-normal rainfall during August-October, increasing 60% during September-November.

Rainfall Prediction

From 25–31 Aug, 45–55 mm is predicted for the Eastern Plains; 25–45 mm is predicted for the Western & Eastern Hills; 5–25 mm is predicted for the Southern Coastal Plains; 0–5 mm is predicted for the Northern, Western & Eastern Plains. From 01–07 Sep, rainfall shall be similar to the previous week. 

(Source: NOAA CPC)

Monitored Rainfall

SL experienced a relatively dry period from 19–24 Aug, with daily average rainfall ranging from 0.2–5 mm. During 19–24 Aug, the average daily rainfall across SL was 1.5 mm. Highest daily rainfall was recorded in Colombo – 33.8 mm on 24 Aug, Hambantota – 23.8 mm on 21 Aug, and Galle – 16.1 mm on 23 Aug.

Monitored Land & Sea Temperature

During 19–24 Aug, average maximum temperature in SL was 32.4°C; Polonnaruwa was the warmest at 38.6°C. The sea surface temperature around SL was warmer by 1.5°C around the Western & Eastern coasts and cooler around the rest of the coasts.

Monitored & Predicted Wind

August generally has the highest winds in Sri Lanka, marking the beginning of the kite-flying season. From 17–23 Aug 2026, winds at 1.5 km elevation were mostly from the  Northwest & West, at speeds of 10–15 m/s. From 26 Aug–01 Sep 2026, winds are predicted to slow down to 8–12 m/s and arrive from the Northwest & Southwest.