Media Center
Climate Bulletin for Sri Lanka (Week of 02-09 May 2025)
Highlights
Rainfall Prediction:During the next week (April 29 – 05 May), “fairly heavy” rainfall (50–100 mm) is predicted for the North-Western, Eastern, Uva, Sabaragamuwa, Central, Southern, and Western provinces, while “moderate” rainfall (25-50 mm) is expected in the North-Central province. “Light showers” are expected in the Northern province.
Monitored Rainfall: During the last 8 days (April 24 – 30), Sri Lanka received an average rainfall of 9.1 mm per day, while the hydro catchment areas recorded an average of 10.1 mm per day. Highest daily rainfall was in Maha Illuppallama on 27th April (77.6 mm).
Monitored and Predicted Wind: From April 21 to 27, winds at 850 mb (1.5 km) from the West at speeds ranging between 3 – 6 m/s. From May 01 to May 07, winds are predicted to come from the South-West, with wind speed ranging between 3-6 m/s.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 32.6 °C in the last week. The Northern plains were the warmest, followed by the Eastern and Southern plains. The sea surface temperature around Sri Lanka ranged between 0.25°C below average and 1.5°C above average from 21 April to 27 April 2025.
Interpretation
Monitoring
Rainfall: Average Rainfall in the Met Stations for the previous week of (24 April – 30 April) = 9.1 mm/day. Maximum Daily Rainfall: 77.6 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: North-Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 3–6 m/s from 21-27 April.
Temperatures: Temperature anomalies were near-neutral across Sri Lanka from April 20 to April 26.
Prediction
Rainfall: During the next week (April 29 – 05May), “fairly heavy” rainfall (50–100 mm) is predicted for the North-Western, Eastern, Uva, Sabaragamuwa, Central, Southern, and Western provinces, while “moderate” rainfall (25-50 mm) is expected in the North-central province. “Light showers” are expected in the Northern province.
Temperatures: The temperature will remain above normal in some parts of the Northern, North-Central provinces, with maximum temperatures reaching up to 37°C of Sri Lanka from May 02 to May 12.
Teleconnections: The MJO will moderately suppress rainfall from April 28 to May 03, neutral rainfall from May 04 to May 08, and moderately enhance rainfall from May 09 to 13 May.
Seasonal Precipitation: The precipitation forecast for the May–June–July 2025 season shows a 40% or more tendency toward above normal precipitation 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 |
