Highlights

Predictions

From 29 July – 24 Aug, the US NOAA Climate Prediction Center predicts that the overall rainfall across Sri Lanka shall increase compared to the previous week. During this period : Western Hills, Western & Southern Plains are predicted to receive rainfall of 35-55 mm. From 30 July – 5 Aug, wind speeds are predicted to be 4-8 m/s from the Northwest.

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 2.1°C above average. Many parts of the Indian Peninsula are experiencing below normal rainfall patterns, consistent with the typical seasonal influence of ongoing El Niño conditions. However, Northeastern and Western India is expected to receive heavy rainfall in the next two weeks. The Tropical Indian Ocean sea surface temperatures currently differs from a typical El Niño influence. According to CCSR/IRI Multi-Model Probability Forecast, Sri Lankais expected to receivemuch heavier rainfall than usual from August onwards. The likelihood increases from 45% during August October to 70% during September-November. This unusually wet weather is caused by the El Niño influence.

Monitoring 

From 19-28 July, Sri Lanka received below-average rainfall (1-2 mm) than typical for July. During 22-28 July, the average daily rainfall was 0.7 mm. The highest daily rainfall was in Ratnapura – 27 mm on 28 July and 15 mm on 15 July. From 21-27 July 2026, winds at 1.5 km elevation were mostly from the Northwest at 6-8 m/s. Overall the temperature was typical for July across Sri Lanka. The Eastern Plains had an average maximum temperature of 36.3°C. The Eastern Hills had an average minimum temperature of 18.2°C.

Rainfall Prediction

From 29 July – 4 Aug; 55-85 mm is predicted for the Western Hills, Western & Southern Plains : 35-55 mm is predicted for the Eastern Hills & Plains, 15-35 mm is predicted for the Northern Plains. From 5-11 Aug, rainfall shall decrease: 35-55 mm is predicted for the Western Hills, Western & Southern Plains : 15-35 mm is predicted for the rest of Sri Lanka. (Source: NOAA CPC)

Monitored Rainfall

During 22-28 July, the average daily rainfall across Sri Lanka was 0.7 mm. From 19- 28 July, Sri Lanka received below-average rainfall (1-2 mm) than typical for July. During 22-28 July, the highest daily rainfall was in Ratnapura – 27 mm on 28 July and 15 mm on 15 July.

Monitored Land & Sea Temperature

During 22-28 July, average maximum temp in Sri Lanka was 33.0°C : higher compared to the previous week – 32.4°C. The Eastern Plains was warmest – 36.3°C. The sea surface temperature around Sri Lanka was warmer by 1.5°C around northern, eastern and western coasts and cooler around northeastern and southern coasts

Monitored & Predicted Wind

From 21–27 July 2026, winds at 1.5 km elevation were mostly from the Northwest at speeds of 6 – 8 m/s. From 30 July – 5 Aug 2026, winds are predicted to slow down to 4-8 m/s and arrive from the Northwest