Media Center
Climate Bulletin for Sri Lanka (Week of 27 June to 4 July 2025)
Highlights
Rainfall Prediction: During the next week (25 June to 01 July), “fairly heavy” rainfall (50–100 mm) is predicted for Galle, Colombo, and Kalutara districts, moderate” rainfall (25-50 mm) is expected in Sabaragamuwa province, Central prov. and Gampaha, and Matara districts, while “light showers” rainfall (12.5-25mm) is predicted for the Northern, North-Central, North-Western, Eastern, and Uva prov. and Hambantota districts.
Monitored Rainfall: During the last 8 days (18 – 25 June), Sri Lanka received an average rainfall of 1.3 mm per day while the hydro catchment areas recorded an average of 9.6 mm per day. Highest daily rainfall was in Ratnapura on 25th June (21.8 mm).
Monitored and Predicted Wind: From June 17 to 23, winds at 1.5 km were mostly from the North-West at speeds ranging between 10-15 m/s. From 26 June to 02 July, winds are predicted to come from the West, and North-West speed ranging between 05-15 m/s.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 35.5 °C in the last week. The Eastern plains were the warmest, followed by the Northern and Southern plains. From 17 to 23 June, the sea surface temperature around Sri Lanka ranged from near-neutral in southern part, to 1.5°C above average in the northern and eastern part.
Interpretation
Monitoring
Rainfall: Average Rainfall in the Met Stations for the previous week of (18 – 25 June) = 1.3 mm/day. Maximum Daily Rainfall: 21.8 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 10-15 m/s from 17-23 June.
Temperatures: Temperature anomalies were near-neutral in Sri Lanka from June 15 to 21.
Prediction
Rainfall: During the next week (25 June to 01 July), “fairly heavy” rainfall (50–100 mm) is predicted for the Galle, Colombo, and Kalutara districts, “moderate” rainfall (25-50 mm) is expected in the Sabaragamuwa prov., Central prov. and Gampaha, and Matara districts while “light showers” rainfall (12.5-25mm) is predicted for the Northern, North-Central, North-Western, Eastern, and Uva prov. and Hambantota districts.
Temperatures: The temperature will remain above normal in some parts of the Northern and Eastern provinces, with maximum temperatures reaching between 37°C and 38°C of Sri Lanka from 27 June to 05 July.
Teleconnections: The MJO will slightly suppress from 25 to 29 June while, moderately suppress from 30 June to 09 July.
Seasonal Precipitation: The precipitation forecast for the July-August-September 2025 season shows a 40% of tendancy below normal in Southern, Western and Sabaragamuwa provinces and 40% tendency toward above normal precipitation in other provinces of Sri Lanka.
Terminology for Rainfall Ranges
| Terminology | Rainfall (mm/week) |
| Light Showers | Less than 12.5 mm |
| Light to Moderate | Between 12.5 mm and 25 mm |
| Moderate | Between 25 mm and 50 mm |
| Fairly Heavy | Between 50 mm and 100 mm |
| Heavy | Between 100 mm and 150 mm |
| Very Heavy | More than 150 mm |
