Highlights

Predictions: From 21 – 27 Apr, the US NOAA Climate Prediction Center predicts that the rainfall shall occur acrossSL.During this period, Western Hills & Plains are predicted to receive rainfall ranging from 55-65 mm. From22- 28Apr,windspeeds are predicted to be 1-2 m/s.
 
 
Monitoring: Sri Lanka is reaching at end of its dry season. During the first three weeks of April (3 – 18 Apr), SLreceived10mm of rainfall than the expected rainfall. During 15 – 22 Apr, the average daily rainfall was 4 mm, a higher rainfall compared to the previous week – 3 mm. The highest daily rainfall was in Maha Illuppallama – 76 mmon20Apr, Badulla-52 mm on 19 Apr and Ratnapura – 35 mm on 15 Apr. During 30 Mar – 5 Apr, winds were fromNortheast with1–3m/s.Overall the temperature was typical for April across SL. The Southern plains had an average maximumtemperatureof33.6°C. The Eastern Hills had an average minimum temperature of 18.3°C.
 

Rainfall Prediction: From 21 – 27 Apr, rainfall is predicted to increase throughout SL: 55-65 mm is predicted for the Western Hills & Western Plains; 45-55 mm is predicted for the Southern Plains and Eastern Hills; 25-45 mm is predicted for the Northern Plains and Eastern Hills. From 28 Apr – 4 May, rainfall shall continue to increase: 35-45 mm is predicted for the Western Hills & Plains, 15-35 mm is predicted for the rest of SL. (Source: NOAA CPC)

 

Monitored Rainfall: Sri Lanka is reaching at the end of its dry season. During the first three weeks of April (3 – 18 Apr), SL received 10 mm of rainfall than the expected rainfall. During 15 – 21 Apr, the average daily rainfall was 4 mm. The highest daily rainfall was in Maha Illuppallama – 76 mm on 20 Apr, Badulla – 52 mm on 19 Apr and Ratnapura – 35 mm on 15 Apr.

 

Monitored Land & Sea Temperature: During 15 – 21 Apr, maximum average temp in SL was 33.4°C, higher compared to the previous week – 33.2°C. Eastern Hills had the lowest temperatures – 28.7°C. The sea surface temperature around Northern and Eastern coasts was above the seasonal average by 1°C – 1.5°C, while it was above the seasonal average by 0.5°C – 1.0°C around the other coasts.
 

Monitored & Predicted Wind: Typical wind reversal in April is ongoing from (North-) East to (South-) West is ongoing. At the lower levels, the reversal is established, while the wind direction has reversed at 1.5km elevation as well. From 13–19 Apr 2026, winds at 1.5km elevation were mostly from the East at 1-3m/s. From 22–28 Apr 2026, winds are predicted to slow (1-2m/s from the South 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