In December, January and February are cloudy and occasional cold fronts can be seen. Although the temperature is low, snow and frost are very unlikely to form. Raining is rare. Once happened, cold and drizzle rain can last long. The winter weather usually ends suddenly when the cold wind stops blowing. Then the spring will come.
From March to May have a higher chance to rain and higher humidity than October and November. But these months are usually welcome by people. The burning summer heat still needs time to arrive.
From June to September are hottest months of the year. Temperature ranges between 26'C to 34'C. Besides, these are the months of thunderstorms. Hong Kong is most likely to be hit by typhoons during summer. Typhoons are classified by size from tropical storms to severe super-typhoons. If the typhoon passes by Hong Kong at a distance, it will bring a little rain and wind that might only last for half a day. If it scores a direct hit, the winds can be deadly and it may rain for days.
Typhoons are violent tropical cyclones, a massive twisting air currents with hundreds of kilometres in width. They can only exist over warm oceans. When they hit the land, their moisture will dry out and they die out. The eye of typhoon is usually tens of kilometres wide and has a column of descending air. It can be entirely calm in contrast to the surrounding vortex.
Hong Kong is only a small point on earth and hence it is not a large target of typhoon. The direct attack by typhoon rarely happens in Hong Kong. When it occurs, the no. 10 signal goes up.
See also: Geography of Hong Kong, Ecology of Hong Kong