El Niño and La Niña
El Niño and La Niña refer to the warming and cooling of surface waters over the central and eastern equatorial Pacific Ocean which affect the atmospheric circulation worldwide and regional climate in many parts of the world. Statistically, the influence of El Niño and La Niña on the climate of Hong Kong when compared to the ENSO-neutral state1 can be summarized below:
1. Generally wetter winter (Dec-Feb) and spring (Mar-May)
2. Unlikely to have tropical cyclones affecting Hong Kong before June.
1. Generally cooler autumn (Sep-Nov) and winter;
2. Likely to have more tropical cyclones affecting the territory during August-October.
Further details are as follows:
1. The ENSO-neutral state refers to the situation with neither an El Niño nor a La Niña in place.