Seasonal Forecast

Seasonal Forecast for October-December 2025

Hong Kong is expecting:

1.	normal to above-normal temperature
2.	normal to above-normal rainfall

Assessment (as of 30 September 2025):

In the past month or so, sea surface temperatures of the central and eastern equatorial Pacific cooled gradually. Based on the latest oceanic observations as well as forecasts by a number of climate models around the world, the sea surface temperatures of the central and eastern equatorial Pacific are expected to continue cooling in the next couple of months, with a possibility of briefly transitioning to La Niña conditions during the rest of this autumn and the winter 2025/26.
Against the backdrop of climate warming, autumn temperatures in Hong Kong exhibit a significant long-term increasing trend. The chance of normal to above-normal temperature is generally higher.
Taking into consideration of the latest ENSO status, different climate model forecasts and other objective forecast guidance, the temperature of October-December 2025 in Hong Kong is expected to be normal to above-normal, and the chance of normal to above-normal rainfall will be slightly higher.

Note:

Climate prediction centres around the world generate seasonal forecasts, employing a variety of methods including dynamical models, statistical methods, expert judgment and combinations of them. Predictions from different centres do not always agree and large discrepancies can occur at times. To formulate seasonal forecasts for Hong Kong, the Observaory takes into consideration available products from major climate prediction centres, past performance of climate models, and impacts of El Niño/La Niña, etc.
The Observatory gratefully acknowledges the Tokyo Climate Center of the Japan Meteorological Agency and the National Centers for Environmental Prediction of National Oceanic and Atmospheric Administration, USA for providing dynamical prediction model forecast and hindcast data to support the formulation of seasonal forecast for Hong Kong.
Seasonal Forecast for November 2025-January 2026 will be available around 1st November 2025.

Seasonal forecast charts provided by major climate centres:

For further information on this webpage, please contact Mr. W P Tse (tel:2926 8012, email:wptse@hko.gov.hk)