Seasonal Forecast

Seasonal Forecast for July-September 2024

Hong Kong is expecting:

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

Assessment (as of 2 July 2024):

In the past month or so, the central and eastern equatorial Pacific continued to cool. Sea surface temperatures of the region returned to normal in May 2024, indicating that the El Niño has ended. Based on the latest oceanic observations as well as forecasts by a number of climate models around the world, the cooling trend of the central and eastern equatorial Pacific is expected to continue in the latter half of 2024. La Nina may start to develop in autumn this year.
Against the backdrop of climate warming, July-September temperatures in Hong Kong exhibit a significant long-term increasing trend. The chance of normal to above-normal temperature is generally higher. Besides, the majority of climate models around the world forecast normal to above-normal temperature over southern China for July-September 2024. Hence, the temperature of July-September 2024 in Hong Kong is expected to be normal to above normal.
Statistical analyses of past performance of climate models around the world do not show a clear consensus of rainfall forecast for the coast of southern China for July-September 2024. Taking into consideration the impact of ENSO-neutral status on July-September rainfall in Hong Kong, the chance of normal to below-normal rainfall in Hong Kong for July-September 2024 is expected to be slightly higher. Nevertheless, Hong Kong may still be affected by heavy rain. Members of the public are reminded to be prepared for the rain season.

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 August-October 2024 will be available around 1st August 2024.

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)