La Niña refers to the cooling of surface waters over the central and eastern equatorial Pacific Ocean which affects the atmospheric circulation worldwide and regional climate in many parts of the world.
Statistically, when compared to normal condition, La Niña tends to be associated with cooler autumn (Sep-Nov) and winter (Dec-Feb), and more tropical cyclones affecting Hong Kong during Aug-Oct. Despite the latter, the Observatory still expects the number of tropical cyclones affecting Hong Kong this year to be 6 or less. The number of tropical cyclones affecting Hong Kong in an average year is 6.4.
Please visit the Hong Kong Observatory website (http://www.hko.gov.hk/lrf/enso/enso-front.htm) for information on El NiãÄ and La Niña.
