Media Center
Climate Bulletin for Sri Lanka (Week of 20 – 27 June 2025)
Highlights
Rainfall Prediction: During the next week (18 to 24 June), “fairly heavy” rainfall (50–100 mm) is predicted for the Western province and Galle, “moderate” rainfall (25-50 mm) is expected in the Central, and Sabaragamuwa prov. and Matara and Kurunegala districts while “light showers” rainfall (12.5-25mm) is predicted for the Northern, North-Central, Eastern, and Uva prov. and Puttalam, and Hambantota districts.
Monitored Rainfall: During the last 8 days (12 – 19 June), Sri Lanka received an average rainfall of 12.5 mm per day while the hydro catchment areas recorded an average of 139.6 mm per day. Most days over the month of June had above-average rainfall levels. Notably, 30th May recorded the highest daily average rainfall of 8.5 mm/day.
Monitored and Predicted Wind: From June 10 to 16 June, winds at 1.5 km were mostly from the North-West at speeds ranging between 15-20 m/s. From 19 to 25 June, winds are predicted to come from the west, speed ranging between 10-15 m/s.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 30.1 °C in the last week. The Oluvil had the warmest, followed by the Trincomalee and Gampaha. From 10 to 16 June, the sea surface temperature around Sri Lanka ranged from near-neutral in southern part, to 1.5°C above average in the northern part.
Interpretation
Monitoring
Rainfall: Average Rainfall in the Airport Stations for the previous week of (12 – 19 June) = 12.5 mm/day. Maximum Daily Rainfall: 121.2 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: Westerly and North-Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 15-20 m/s from 10-16 June.
Temperatures: Temperature anomalies were slightly cooler in the Kurunegala, Anuradhapura, and Polonnaruwa districts, while near neutral in other parts of Sri Lanka from June 8 to 14.
Prediction
Rainfall: During the next week (18 to 24 June), “fairly heavy” rainfall (50–100 mm) is predicted for the Western province and Galle, “moderate” rainfall (25-50 mm) is expected in the Central, and Sabaragamuwa prov. and Matara and Kurunegala districts while “light showers” rainfall (12.5-25mm) is predicted for the Northern, North-Central, Eastern, and Uva prov. and Puttalam, 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 20 to 29 June.
Teleconnections: The MJO will near neutral from 17 June to 01 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 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 |
