Hong Kong's climate is sub-tropical, tending towards the temperate for nearly half the year. November and December are generally regarded as the best months of the year with pleasant breezes, plenty of sunshine and comfortable temperatures.

January and February are cloudier, with occasional cold fronts bringing in cold northerly winds. Temperatures can drop below 10 degrees Celsius in urban areas. Sub-zero temperatures and frost occur on high ground and in the New Territories infrequently.

March and April can be mild and pleasant but humid. Fog and drizzle sometimes disrupt air traffic and ferry services because of reduced visibility.

The months from May to August are hot and humid with occasional showers and thunderstorms, particularly in the morning. Afternoon temperatures often exceed 31 degrees, but at night temperatures generally remain around 26 degrees.

Hong Kong is most likely to be affected by tropical cyclones in September, although tropical cyclones of varying strength are not unusual at any time between May and November. On average, about 31 tropical cyclones form over the western North Pacific and the China Seas every year, and about half of them reach typhoon strength with maximum winds of 118 kilometres per hour or more.

When a tropical cyclone is about 700 to 1 000 kilometres southeast of Hong Kong, the weather is usually fine and exceptionally hot, but isolated thunderstorms sometimes occur in the evening. If the cyclone's centre comes closer to Hong Kong, winds will increase and rain may become heavy and widespread. The heavy rain may last a few days, and landslips and flooding sometimes cause considerably more damage than the winds.

The mean annual rainfall ranges from around 1 300 millimetres at Waglan Island to more than 3 000 millimetres around Tai Mo Shan. About 80 per cent of the rain falls between May and September. August is the wettest month with an average rainfall of 391.4 millimetres at the Hong Kong Observatory and, on average, rain falls on more than half of the days. The driest month is January with only 23.4 millimetres of rain and six rain days on average.

Severe weather phenomena in Hong Kong include tropical cyclones, strong winter and summer monsoon winds, monsoon troughs and thunderstorms with associated squalls. Waterspouts and hailstorms occur infrequently, while snow and tornadoes are rare.

Climatological data are given in the Appendices.

The year 2000 was warmer and wetter than usual. The mean temperature of 23.3 degrees was the eighth highest on record and the mean minimum temperature of 21.5 degrees was the sixth highest, The annual total rainfall of 2 752.3 millimetres was 24 per cent above normal. The mean atmospheric pressure of 1 011.9 hectopascals was the fifth lowest recorded. Seven tropical cyclones necessitated the hoisting of Tropical Cyclone Warning Signals. However, no Signal No.8 or higher was hoisted.

January was warmer and wetter than usual. The monthly mean temperature was 1.2 degrees higher than normal.

It was cooler and drier than normal in February.

March was again drier but warmer than normal.

April was warmer than normal and marked by unsettled weather and heavy rain. The total rainfall of 547.7 millimetres, more than three times the normal figure, was the highest recorded for April. The Black Rainstorm Warning Signal was issued on April 23.

May was drier than normal. Prolonged periods of sunshine brought very hot weather to Hong Kong on the last three days of the month. The Very Hot Weather Warning was issued for the first time, on May 29.

June remained warmer than usual. Despite a mean relative humidity of only 78 per cent, the lowest recorded for June, the month was also rainier than usual. The Black Rainstorm Warning Signal was issued on June 12. A tropical depression formed rapidly over the waters just to the south of Lantau Island on June 18. It necessitated the direct hoisting of the Strong Wind Signal No. 3. The tropical depression then crossed Hong Kong waters and landed near Tsuen Wan before dissipating rapidly.

July was slightly drier than normal. Typhoon Kai-tak and another Tropical Depression necessitated the hoisting of the Standby Signal No. 1.

Hong Kong was affected by unsettled weather with heavy rain due to passages of troughs of low pressure and tropical cyclones in August. The Standby Signal No. 1 was hoisted for Typhoon Bilis and Severe Tropical Storm Maria respectively during the month. The Black Rainstorm Warning Signal was issued on August 24.

September was drier and slightly warmer than usual. Severe Tropical Storm Maria headed towards the South China coast in the early morning of September 1 and the Strong Wind Signal No. 3 was hoisted. Typhoon Wukong also necessitated the hoisting of the Strong Wind Signal during the month.

October was warmer and wetter than normal. It was also a windy month with the Strong Monsoon Signal hoisted on 13 days.

It was cooler and wetter than usual in November. During the passage of Severe Tropical Storm Bebinca, the Tropical Cyclone Warning Signal was hoisted for 89 hours, the longest duration for a tropical cyclone in November.