Fact · climate · 1991-2020
Mean annual rainfall
平均全年雨量
Figure and reference date
2,431.2 mm
2 431.2 毫米
Notes and definition
GovHK uses this long-term mean. Hong Kong in Figures 2026 also lists 1991–2020 normals; recorded rainfall in 2025 was 2,558.7 mm.
Other figures in this group (climate)
Figures in the same group are not necessarily additive — check the basis note above first. Climate.
| Item / 項目 | Figure / 數字 | As of / 時點 | Source / 來源 |
|---|---|---|---|
| Annual mean air temperature (normal) 全年平均氣溫（正常值） | 23.5°C 23.5°C | 1991-2020 | Hong Kong in Figures, 2026 Edition |
| Record maximum temperature at the Observatory 天文台最高氣溫紀錄 | 39.0°C on 22 July 2022 39.0°C（2022 年 7 月 22 日） The highest temperature since the Observatory began records in 1884. Extreme-heat days are updated annually by the HKO. | 2022-07-22 | Hong Kong Fact Sheet |
| Record minimum temperature at the Observatory 天文台最低氣溫紀錄 | 0.0°C on 18 January 1957 0.0°C（1957 年 1 月 18 日） The lowest temperature at the urban Observatory; uplands and the countryside can be colder, per separate station records. | 1957-01-18 | Hong Kong Fact Sheet |
| Very Hot Weather days 酷熱天氣日數 | 53 days (2025; third most on record) 53 天（2025，有紀錄以來第三多） HKO Year 2025: days with max ≥33°C. | 2025 | Hong Kong Observatory: The Year 2025 |
| Hot nights 熱夜數目 | 54 nights (2025; third most on record) 54 天（2025，有紀錄以來第三多） HKO: nights with min ≥28°C. | 2025 | Hong Kong Observatory: The Year 2025 |
| Thunderstorm days in a year 全年雷暴日數 | 37 days (2025) 37 天（2025） HKO does not publish a year total for lightning; thunderstorm days used as proxy. | 2025 | Hong Kong Observatory: The Year 2025 |
Other figures from the same official source
These figures come from the same registered document: “Hong Kong Fact Sheet” (GovHK). Being in one document does not make them additive.
| Item / 項目 | Figure / 數字 | As of / 時點 | Source / 來源 |
|---|---|---|---|
| Population density 人口密度 | 6,870 persons per km² 每平方公里 6 870 人 As at mid-2025. Census and Statistics Department also publishes density by Hong Kong Island, Kowloon, and the New Territories and Islands. | 2025-06 | Hong Kong Fact Sheet |
| Philippine nationals present in Hong Kong 身在香港的菲律賓國籍人士 | 195,574 195 574 人 Immigration Department movement count for one day, not the stock of foreign residents with a right of abode, and not additive with census ethnicity figures. | 2025-12 | Hong Kong Fact Sheet |
| Indonesian nationals present in Hong Kong 身在香港的印度尼西亞國籍人士 | 182,215 182 215 人 Immigration Department movement count for one day, not the stock of foreign residents with a right of abode, and not additive with census ethnicity figures. | 2025-12 | Hong Kong Fact Sheet |
| Indian nationals present in Hong Kong 身在香港的印度國籍人士 | 39,587 39 587 人 Immigration Department movement count for one day, not the stock of foreign residents with a right of abode, and not additive with census ethnicity figures. | 2025-12 | Hong Kong Fact Sheet |
| Share of population who are Chinese 華人佔人口比例 | 91.6% 91.6% 2021 Population Census. | 2021 | Hong Kong Fact Sheet |
| Crude birth rate臨時 粗出生率 | 4.1 per 1,000 population 每千名人口 4.1 人 Provisional figure. | 2025 | Hong Kong Fact Sheet |
| Number of islands 島嶼數目 | 261 islands of 500 m² or more, excluding Hong Kong Island and Lantau Island 261 個（面積 500 平方米或以上，不包括香港島及大嶼山） | 2026-07 | Hong Kong Fact Sheet |
| Country parks and special areas 郊野公園及特別地區 | About 40% of land 約佔土地 40% | 2026-07 | Hong Kong Fact Sheet |
15 more figures come from the same document; see Climate.
Verified questions that cite this figure
When do typhoons hit Hong Kong?
Tropical cyclones can affect Hong Kong at any time of year but cluster in late summer and early autumn. In practice, what matters is the Observatory’s warning signal — 1, 3, 8, 9 or 10.
Why is Hong Kong so hot, humid and rainy?
Hong Kong has a subtropical climate: the annual mean temperature is about 23.5°C and annual rainfall about 2,431.2 mm. Summer heat comes from the ocean, the monsoon and the density of the built city.
How are Hong Kong water charges calculated?
Domestic water charges are tiered by volume, billed every four months. The per-cubic-metre tiers are published by the Water Supplies Department, alongside sewage charges and flushing-water charges.
Why is athlete’s foot called “Hong Kong foot” in Chinese?
“Hong Kong foot” is the Chinese colloquial name for athlete’s foot (tinea pedis). It dates to the nineteenth and early twentieth centuries, when British troops and residents in Hong Kong’s hot, humid climate commonly developed the infection — the name followed them home. The condition is not unique to Hong Kong.
What is the hottest temperature ever recorded in Hong Kong and which was the hottest year?
The Hong Kong Observatory daily series since 1885 shows a clear rise in both mean temperature and hot nights in recent decades. The annual mean of 24.6°C in 2023 was among the warmest on record; very hot days reach 36.1°C or above and trigger the Very Hot Weather Warning.
Hong Kong rainfall concentrates in late spring, early summer and the summer months under the monsoon and typhoon seasons. The Observatory publishes monthly and annual rainfall, typhoon tracks and tropical-cyclone statistics with explicit reporting periods.
When is the rainy season in Hong Kong?
Hong Kong’s mean annual rainfall is about 2,431 mm (1991–2020 normal), concentrated from May to September with July the wettest month; winter (December–February) is drier. Summer typhoons and the south-west monsoon bring heavy rain.
Why is Hong Kong so humid and muggy?
Hong Kong has a sub-tropical monsoon climate; from early to late summer the south-west monsoon brings high temperature, heavy rain and persistently high humidity. The annual mean temperature is about 23.5°C (1991–2020 normal), so muggy heat is common in summer.
（已核對問題頁目前只有中文版；上面嘅英文標題同答案本身係資料檔嘅官方英文欄位。）
How to cite this figure
Hong Kong Story, “Mean annual rainfall”, https://hongkongstory.org/en/facts/rainfall-normal, data as at 1991-2020 (retrieved ＿).
中文：香港紀事館，〈平均全年雨量〉，https://hongkongstory.org/facts/rainfall-normal，資料時點 1991-2020（查閱日期 ＿）。
Machine-readable: /api/v1/facts.json (id = rainfall-normal) · OpenAPI 3.1 ·/llms.txt
Registered source
GovHK
Official document dated 2026-07; last checked by this site 2026-09-05.
This site is a secondary compilation: the official text prevails. If the figure above differs from the official document, the official document is correct.