Highlights

Predictions

Rainfall: From 13-19 Oct, the US NOAA Climate Prediction Center predicts that southwestern and central areas of SL are predicted to receive very heavy rainfall of 115-135 mm; while Eastern and Northern Plains are predicted to receive 65-105 mm. During Oct-Dec, there is a 50% likelihood of SL receiving higher-than-normal tercile rainfall (Source: CCSR/IRI multi-model Probability prediction). Wind: From 14-20 Oct 2026, winds are predicted to slow down to 1-3 m/s, arriving mostly from the South and Southeast. The predictions for the coming week shows a shift in wind direction from easterly to southeasterly winds.

Monitoring

Rainfall: During 7-13 Oct, there was extremely heavy rainfall in western and southwestern regions, with Puttalam receiving the highest daily rainfall of 96 mm on 8 Oct. Highest average rainfall was in Western Hills – 14.7 mm and Western Plains – 14.4 mm. During 7-13 Oct, the average daily rainfall across SL was 10 mm. Wind: From 5 – 11 Oct 2026, winds at 1.5 km elevation were mostly from the Northeast at speeds of 1-5 m/s. Temperature: Overall, temperature was typical for October across SL, with Northern Plains being relatively warmer (33.1°C). The warmest regions were: Northern Plains with an average maximum temperature of 33.1°C & Eastern Plains with an average maximum temperature of 32.8°C. The coldest region at night was the Eastern Hills with an average minimum temperature of 18.6°C.

Indian Ocean (IO) SST

According to CCSR/IRI climate forecasts, there is 90-95% probability of a positive IOD from October through December 2026. The Dipole Mode Index (DMI) of the current positive IOD (Indian Ocean Dipole) phase has increased to +0.76°C from +0.68°C last week, indicating a strengthening of the positive IOD conditions. A positive dipole event is identified at DMI > 0.4.

El Niño Event

El Niño conditions continue to prevail across the equatorial Pacific Ocean (Niño 3.4 region). Currently, sea surface temperature (SST) in the Niño 3.4 region is 3.0°C above average – this is one of the strongest El Nino events already.

Rainfall Prediction

From 13–19 Oct, the Southwestern and Central regions are predicted to receive extremely heavy rainfall exceeding 135 mm.115–135 mm is predicted for the Western and Eastern Hills, Southern and Western Plains; 65–105 mm is predicted for the Eastern and Northern Plains.From 20–26 Oct, 115–135 mm is predicted for the Western Hills, Southern and Western Plains. (Source: NOAA CPC)

Monitored Rainfall

During 7–13 Oct, there was extremely heavy rainfall in the Western and Southwestern regions, with Puttalam recording the highest daily rainfall of 96 mm on 8 Oct. The highest average rainfall was recorded in the Western Hills (14.7 mm) and Western Plains (14.4 mm). During 7–13 Oct, the average daily rainfall across SL was 10 mm.

Monitored Land & Sea Temperature

Overall, temperature was typical for October across SL, with the Northern Plains being relatively warmer (33.1°C). During 7–13 Oct, the average maximum temperature in SL was 31.8°C, lower than the previous week’s average of 32.6°C. The sea surface temperature around SL was 2.0–2.5°C warmer than the seasonal average around the Western coasts and 1.0–1.5°C warmer around the rest of the coasts.

Monitored & Predicted Wind

The winds during the last week were from the Northeast at low speeds. Predictions for the coming week show a shift in wind direction from northeasterly to southeasterly winds. From 5–11 Oct 2026, winds at 1.5 km elevation were mostly from the Northeast, at speeds of 1–5 m/s. From 14–20 Oct 2026, winds are predicted to slow down to 1–3 m/s, arriving mostly from the South and Southeast.