Highlights

Predictions: From 5 – 11 May, the US NOAA Climate Prediction Center predicts that the rainfall shall increase across SL. During this period, Western Hills & Plains are predicted to receive rainfall over 135 mm. From 6 – 12 May, wind speeds are predicted to be 1-3 m/s.
 
Monitoring: Rainfall in Sri Lanka has picked up after several dry weeks. During 29 Apr – 5 May, the average daily rainfall was 4.5 mm. The highest daily rainfall was in Mullaitivu – 75 mm on 4 May, Bandarawela – 41 mm on 2 May. During 27 Apr – 3 May, winds were from Southwest with 2–3 m/s. Overall the temperature was typical for April across SL. The Eastern Plains had an average maximum temperature of 35.0°C. The Eastern Hills had an average minimum temperature of 19.4°C.
 

Rainfall Prediction: From 5 – 11 May, rainfall is predicted to increase throughout SL: over 135 mm is predicted for the Western Hills & Plains; 105-135 mm is predicted for the Southern Plains and Eastern Hills; 85-105 mm is predicted for the Northern & Eastern Plains. From 12 – 18 May, rainfall shall decrease: 105-125 mm is predicted for the Western Plains and 45-105 mm rainfall for the rest of SL. (Source: NOAA CPC)

Monitored Rainfall: Rainfall in Sri Lanka has picked up after several dry weeks. During 29 Apr – 5 May, the average daily rainfall was 4.5 mm. The highest daily rainfall was in Mullaitivu – 75 mm on 4 May, Bandarawela – 41 mm on 2 May.

 

Monitored Land & Sea Temperature: During 29 Apr – 5 May, maximum average temp in SL was 33.0°C, higher compared to the previous week – 32.9°C. Eastern Hills had the lowest temperatures – 28.7°C. The sea surface temperature around SL was above the seasonal average by 1°C – 1.5°C.
 

Monitored & Predicted Wind: From 27 Apr – 3 May 2026, winds at 1.5 km elevation were mostly from the Southwest at 2 – 3 m/s. From 6 – 12 May 2026, winds are predicted to slow down ( 1-3 m/s from the Northwest).



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