Blogs
Climate Bulletin for Sri Lanka (Week of 11 July to 18 July 2025)
Highlights
Rainfall Prediction: During the next week, 25-35 mm/week rainfall is expected in the Gampaha, Colombo, Kegalle, Kandy districts, while 15-25 mm/week rainfall is predicted for the North-Western province and Matale, Nuwara Eliya, Rathnapura, Kaluthara districts, while 0-15 mm/week are predicted for the North, North-Central, Eastern, Uva, Southern provinces.
Monitored Rainfall: During the last 8 days (2-9 July), Sri Lanka received an average rainfall of 0.4 mm/day, while in the hydro catchments, the average rainfall was 0.9 mm/day.
Highest daily rainfall was in Galle on 5th July (17 mm).
There is a noticeable drop in daily rainfall, starting from 17th June.
Monitored and Predicted Wind: From July 1 to 7, winds at 1.5 km was mostly from the North-West at speeds ranging between 10-15 m/s. From 10-16 July, winds are predicted to come from the North-West at speed ranging between 10-20 m/s.
Monitored Sea and Land Temperature: Average maximum land surface temperature was 32.9 °C in the last week. The Eastern Plains were the warmest, followed by Southern and Northern Plains. From 1 to 7 July, the sea surface temperature is near-neutral around the Southern coast, while it is warmer around the Eastern coast and South-Western coast.
Interpretation
Monitoring
Rainfall: Most days of the second half of June and first half of July had below-average rainfall levels. Notably, only 26th June recorded an above-average rainfall level with a daily average rainfall of 3 mm/day.
Wind: North-Westerly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 10-15 m/s from 1-7 July.
Temperatures : Temperature anomalies were near-neutral in Sri Lanka except for Western, Sabaragamuwa provinces and some parts in North-Western, Central, Northern and Southern provinces from June 29 to July 5.
Prediction
Rainfall: During the next week, 25-35 mm/week rainfall is expected in the Gampaha, Colombo,Kegalle, Kandy districts, while 15-25 mm/week rainfall is predicted for the North-Western province and Matale, Nuwara Eliya, Rathnapura, Kaluthara districts, while 0-15 mm/week are predicted for the North, North-Central, Eastern, Uva, Southern provinces.
Temperatures: The temperature will remain above normal in some parts of the Northern, Eastern, Uva, North-Central and Southern provinces, with maximum temperatures reaching between 37°C and 39°C of Sri Lanka from 12-15 July.
Teleconnections: The MJO will be near neutral from 9 to 23 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 Northern 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 |
