Blogs
Climate Bulletin for Sri Lanka (Week of 01 – 08 August 2025)
Highlights
Rainfall Prediction: For 29 July-04 August, rainfall/week is expected as 25-35 in the Kandy district, 15-25 in the Matale, Nuwara Eliya, Badulla districts, 0-15 in the Northern, North-Central, Eastern, Sabaragamuwa, Southern, Western, North-Western provinces and Moneragala district.
Monitored Rainfall: During July 22-29, Sri Lanka received an average rainfall of 2 mm/day, while in the hydro catchments, the average rainfall was 7 mm/day. After a sharp drop in rainfall during the first half of July, rain picked up again in the second half, starting from the 16th.
Monitored and Predicted Wind: From July 21 to 27, winds at 1.5 km was mostly from the North-West at speeds ranging between 15-20 m/s. From 30 July – 05 August, wind speeds are predicted to be ranging between 4-15 m/s and expected to come from the North-West.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 31.8 °C during 22-29 July. The Eastern Plains were the warmest, followed by Southern and Northern Plains. From 21 to 27 July, the sea surface temperature is cooler around the Southern coast, ranging between 0.5 °C to 1.0 °C below-average levels while it is warmer around the Eastern and North-Western coasts, ranging between 0.5 °C to 1.5 °C above-average levels.
Interpretation
Monitoring
Rainfall: Average Rainfall in the Met stations for the previous week of (22-29 July) = 2.1 mm/day. Maximum Daily Rainfall: 34.6 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 15-20 m/s from 21-27 July.
Temperatures: Temperature anomalies were near-neutral in Sri Lanka except for some parts in Sabaragamuwa province from July 20 to 26.
Prediction
Rainfall: During the next week, 25-35 mm/week rainfall is expected in the Kandy district while 15-25 mm/week rainfall is predicted for the Matale, Nuwara Eliya, Badulla districts, while 0-15 mm/week rainfall is predicted for the Northern, North-Central, Eastern, Sabaragamuwa, Southern,Western, North-Western provinces and Moneragala district.
Temperatures: The temperature will remain above normal in Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Batticaloa, Ampara, Moneragala, Hambantota districts with maximum temperatures reaching between 36°C and 39°C of Sri Lanka from 30 July – 4 August.
Teleconnections: The MJO will moderately suppress the rainfall from 29 July to 2 August, slightly suppress the rainfall from 3 to 7 August, near-neutral from 8 to 12 August.
Seasonal Precipitation: The precipitation forecast for the September-October-November 2025 season shows a 40% of tendancy above normal in Eastern province 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 |
