Projections of the annual number of rain days, annual number of extreme rainfall days, average rainfall intensity and the annual maximum number of consecutive dry days in Hong Kong

25 March 2025

The Hong Kong Observatory used the climate model data from the Sixth Assessment Report of the Intergovernmental Panel on Climate Change and adopted contemporary statistical methods to update the projections of the 20-year average of the annual number of rain days, annual number of extreme rainfall days, average rainfall intensity and the annual maximum number of consecutive dry days in Hong Kong in the 21st century.

The results showed that, under intermediate to very high greenhouse gas concentration scenarios, while there is no significant trend in the annual number of rain days in Hong Kong throughout this century, the annual number of extreme rainfall days and the average rainfall intensity (i.e. annual rainfall divided by the number of rain days) are expected to increase.