Highlights

Rainfall Prediction: For 22-28 July, rainfall/week is expected as 25-35 in the Galle, Ratnapura, Matara districts, 15-25 in the Western, North-Western, Central Provinces, and Hambantota, Kegalle districts, 0-15 in the Northern, Eastern, Uva, North-Central Prov.

Monitored Rainfall: In the first half of July, Sri Lanka only received 20 mm of rainfall, even though the average rainfall for July is around 40 mm.During July 15-22, Sri Lanka received an average rainfall of 3.0 mm/day, while in the hydro catchments, the average rainfall was 20 mm/day.

Monitored and Predicted Wind: From July 14 to 21, winds at 1.5 km were mostly from the North-West at speeds ranging between 10-20 m/s. Monitored & Predicted Wind From 24-30 July, wind speeds are predicted to range between 10-15 m/s and are expected to come from the Northwest.

Monitored Sea and Land Temperature: The average maximum land surface temperature was 31.6 °C during 15 22 July. The Eastern Plains were the warmest, followed by the Southern and Northern Plains. Monitored Land & Sea Temp From 14 to 20 July, the sea surface temperature is near-neutral around the Southern coast, while it is warmer around the Eastern and North-Eastern coasts.

 

 

Interpretation

Monitoring

Rainfall: There was a drastic rainfall decline in the last two weeks, receiving only 20 mm compared to the normal rainfall level of 40 mm. This condition indicates a potential drought condition in Sri Lanka during this period.

Wind: North-Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 10-20 m/s from 14-20 July.

Temperatures  :Temperature anomalies were near neutral in Sri Lanka from July 13 to 19.

Prediction

Rainfall: During the next week, 25-35 mm/week rainfall is expected in the Galle, Ratnapura, Matara districts while 15-25 mm/week rainfall is predicted for the Western, Central, North Western provinces and Hambantota, Kegalle districts, while 0-15 mm/week rainfall is predicted for the Northern, Uva, North-Central, Eastern provinces.

Temperatures: The temperature will remain above normal in some parts of the Eastern, Uva, and Northern provinces, with maximum temperatures reaching between 34°C and 38°C of Sri Lanka from 26 July – 1 August.

Teleconnections: The MJO will moderately suppress the rainfall from 22 July to 5 August.

Seasonal Precipitation: The precipitation forecast for the August-September-October 2025 season shows a 40% of tendency below normal in Southern, Western, Central, Uva, and Sabaragamuwa provinces of Sri Lanka.

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