Highlights

Rainfall Prediction: During the next week, “moderate” rainfall (25-50 mm) is expected in the Western prov. and Galle, Matara, Kandy, Kegalle districts while “light to moderate” rainfall (12.5-25mm) is predicted for the North-Western prov. and Rathnapura, Nuwara eliya, Matale Hambantota districts, while “light showers” are predicted for the Nothern, Eastern, North-Central and Uva provinces.

Monitored Rainfall: During the last 8 days (18 – 25 June), Sri Lanka received an average rainfall of 0.6 mm per day. Most days of the second half of June had below-average rainfall levels, only 26th June recording an above-average rainfall level of 3mm. Highest daily rainfall was in Colombo on 26th June (14 mm).

Monitored and Predicted Wind: From June 24 to 30, winds at 1.5 km was mostly from the North-West at speeds ranging between 10-15 m/s.
From 3-9 July, winds are predicted to come from the North-West at speed ranging between 5-15 m/s.

Monitored Sea and Land Temperature: Average maximum land surface temperature was 29.5 °C in the last week. The Trincomalee was the warmest, followed by Katunayake and Colombo. From 24 to 30 June, the sea surface temperature around Sri Lanka ranged from 0.5°C above-average in Southern part, to 1.5°C above-average in the Northern, Western and Eastern part.

 

Interpretation

Monitoring

Rainfall: Most days of the first half of June had above-average rainfall levels, while most days of the second half had below-average rainfall levels. Notably, 10th June recorded the highest daily average rainfall of 8 mm/day.

Wind: North-Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 10-15 m/s from 24-30 June.

Temperatures: Temperature anomalies were near-neutral in Sri Lanka from June 15 to 21.

Prediction

Rainfall: During the next week (2-8 July), “moderate” rainfall (25-50 mm) is expected in the Western prov. and Galle, Matara, Kandy, Kegalle districts while “light to moderate” rainfall (12.5-25mm) is predicted for the North-Western prov. and Rathnapura, Nuwara eliya, Matale Hambantota districts, while “light showers” are predicted for the Nothern, Eastern, North-Central and Uva provinces.

Temperatures: The temperature will remain above normal in some parts of the Northern, Eastern, Uva and Southern provinces, with maximum temperatures reaching between 37°C and 38°C of Sri Lanka from 4-12 July.

Teleconnections: The MJO will be near neutral from 2 to 11 July and slightly enhance the rainfall from 12-16 July.

Seasonal Precipitation: The precipitation forecast for the July-August-September 2025 season shows a 40% of tendency below normal in Southern, Western and Sabaragamuwa provinces and 40% tendency toward above normal precipitation in Northern province 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