Media Center
Climate Bulletin for Sri Lanka (Week of 25 April – 02 May 2025)
Highlights
Rainfall Prediction: During the next week (April 23–29), “fairly heavy” rainfall (50–100mm) is predicted for the Western, Uva, Sabaragamuwa and Central Provinces, while “moderate” rainfall (25- 50 mm) is expected in the Southern, Eastern, North-Central, North- Western Provinces. “Light showers” are expected in the
Northern Province.
Monitored Rainfall: During the last 8 days ( 16 – 23 April), Sri Lanka received an average rainfall of 5.5 mm per day, while the hydro catchment areas recorded an average of 4.9 mm per day. Highest daily rainfall was in Trincomalee on 16th April (43.8mm).
Monitored and Predicted Wind: From April 15 to 21, winds at 850 mb (1.5 km) from the North- west at speeds ranging between 2 – 5 m/s. From April 24 to April 30, winds are predicted to come from the south-west, with wind speed speed of 3 m/s.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 32.7 °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 and 1.0°C above average from 15 April to 21 April, 2025.
Interpretation
Monitoring
Rainfall: Average Rainfall in the Met Stations for the previous week of (16 Apr – 23 Apr) = 5.5 mm/day. Maximum daily rainfall: 43.8mm and Minimum daily rainfall: 0.0mm.
Wind: Northwesterly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 2–5 m/s from 15 Apr – 21 Apr.
Temperatures: Temperature anomalies were near-neutral across Sri Lanka from April 13 to April 19.
Prediction
Rainfall: During the next week (April 23–29), “fairly heavy” rainfall (50–100 mm) is predicted for the Western, Uva, Sabaragamuwa and Central Provinces, while “moderate” rainfall (25-50 mm) is expected in the Southern, Eastern, North-Central, North-Western Provinces. “Light showers” are expected in the Northern Province.
Temperatures: The temperature will remain above normal in some parts of the Northern and North-Central Provinces, with maximum temperatures reaching up to 37°C, while it will remain normal in other parts of Sri Lanka from April 19 to April 28.
Teleconnections: The MJO will significantly suppress rainfall from April 22 to 27, moderately suppress rainfall from April 28 to May 1, and slightly enhance rainfall from May 2 to 6 May.
Seasonal Precipitation: The precipitation forecast for the May–June–July 2025 season shows a 40% or more tendency toward above normal precipitation across 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 |
