Blogs
Climate Bulletin for Sri Lanka (Week of 21 November – 28 November 2025)
Highlights
Rainfall Prediction: From 18th -24th Nov, heavy rainfall (105-135 mm) is predicted for the Western plains, Western hills and Northern Plains; while fairly heavy rainfall (55-105 mm) is predicted for the Southern plains , Eastern plains and Eastern hills. From 25th Nov -1st Dec , the rainfall shall show a further decrease, with a similar spatial pattern.
Monitored Rainfall:During 11th – 17th November, the average rainfall across Sri Lanka totalled 95 mm. There was higher rainfall across the Northern plains and Eastern plains especially in Batticaloa with a maximum of 143 mm on 14th November.
Monitored and Predicted Wind: From 10th -16th Nov, winds at 1.5 km height were mostly from the northeast at speeds ranging 3-6 m/s. From 19th-25th Nov, wind speeds are predicted to be in the range of 4-10 m/s coming from the North East and North West.
Monitored Sea and Land Temperature: Sri Lanka recorded seasonable temp across its regions. The Southern plains were the warmest, with maximum temp of 31.4°C. The sea surface temp was warmer than average around Sri Lanka, ranging between 0.3°C and 1°C above average.
Interpretation
Monitoring
Rainfall: Average Rainfall in the regions for the previous week of (12-18 November) = 13.6 mm/day. Maximum Daily Rainfall: 142.9 mm & Minimum Daily Rainfall: 0.0 mm.
Wind: North-Easterly winds prevailed over the sea area and around the island last week, with wind speeds ranging between 3-6 m/s from 10 – 16 Nov.
Temperatures: During the period 9 – 15 Nov, Sri Lanka experienced near-neutral conditions except in some parts in Sabaragamuwa and central provinces.
Prediction
Rainfall: From 18 – 24 November, rainfall is expected to be 105–135 mm/week in WP, WH and NP regions; 55-105 mm/week in EH, SP and EP regions.
Temperatures: From 20 November – 03 December, temperature will remain normal for Sri Lanka. (Source: SL Met Dept).
Teleconnections: The Madden-Julian-Oscillation (MJO) will moderately suppress from 17th Nov – 01st Dec.
Seasonal Precipitation: The forecast for the December-January-February 2026 season shows high tendency towards the near-neutral tercile.
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 |
