Introduction
In recent years, extreme weather such as scorching high temperatures, super typhoons and torrential rain affected Hong Kong and various parts of the world. Issues in connection with climate change, including melting ice in polar region and rising sea levels, were also in the spotlight. While weather is closely connected with our daily lives, extreme weather events like extreme heat and rainfall are becoming more frequent under global warming, bringing severe damages and even loss of life to different parts of the world. The Hong Kong Observatory, in collaboration with the Hong Kong Meteorological Society, is organising a public activity "2021-2025 Top 10 Mind-boggling Weather and Climate Events Selection" to invite public attention to the high-impact weather and climate events in Hong Kong and around the world over the past 5 years, with a view to raising the public's awareness and understanding on extreme weather and climate change, as well as the concerns over the ecological environment.
Thank you for your support. This activity had attracted near 2,000 votes. The top 5 weather and climate events with the highest number of votes in each of the "Hong Kong" and "Worldwide" categories are as follows. Winners will be notified by email.
- Participants should select 5 weather and climate events which are considered most significant, impactful or representative as a manifestation of climate crisis from each of the "Hong Kong" category and "Worldwide" category on the designated website of the Observatory during the voting period.
- The voting period starts on 29 January, 2026 and ends at 23:59:59 on 28 February, 2026, based on the time of reception at the server of this website. Late submissions will not be entertained.
- Each participant can only vote once. If repetitive votes were found, the related voting records may be discarded.
- If a participant whose 5 choices in either the "Hong Kong" or "Worldwide" category match the 5 events with the highest number of votes, he/she may win a set of exquisite souvenirs from the Observatory. 200 sets of souvenirs for each category will be given to the first 200 winning participants based on the time they cast the vote.
- If a participant wishes to win the souvenirs from this event, he/she needs to provide an email address for communication use. The personal data provided by the participant will be used only for the abovementioned purpose, and will be destroyed at appropriate time after the event. In accordance with Section 18, Section 22 and Principle 6 of Schedule 1 to the Personal Data (Privacy) Ordinance, you have the right to request access and correct the personal data you provided.
- If a participant does not wish to provide his/her email address, his/her vote would still be valid but he/she would lose the chance to win any souvenir. If the information submitted by the participant is inaccurate or incomplete, making the Observatory unable to contact the winner, verify his/her identity and/or arrange for souvenir redemption, he/she will be disqualified from winning souvenir.
- Cookies or similar technologies are employed on the voting webpage to save users' voting information and settings to ensure the effective operation of the website. Such information and settings are only stored on the users’ computer or mobile device. No personally identifiable information would be collected and saved by cookies. If users opt for not accepting cookies by changing browser settings, they may not be able to participate in the voting.
- Each email address is eligible for winning souvenirs once only. The results of the campaign will be announced tentatively in late March 2026. Winners will also be notified via email afterwards.
- In case of any dispute, the decision of the Hong Kong Observatory shall be final.
"Hong Kong" Category
Affected by tropical cyclone Rai, the Hong Kong Observatory issued the Standby Signal No. 1 on the morning of 20 December 2021. Breaking the record of Irma in 1974, Rai became the storm which necessitated the issuance of the latest tropical cyclone warning signal in a year since 1946. All tropical cyclone warning signals were cancelled on the following day (21 December 2021), the Winter Solstice, marking the first time since 1946 that a tropical cyclone warning was in force during the Winter Solstice.
Read more: Rai – The record-breaking tropical cyclone
There were 61 hot nights and 54 hot days in 2021, both were the highest on record. Between 1961 and 1990, there were on average around 9 hot nights and 13 to 14 very hot days annually.
Read more: The Year's Weather – 2021
July 2022 was the hottest month on record with a record-breaking mean temperature of 30.3 degrees.
Read more: The Weather of July 2022
There were 15 extremely hot days in 2022 and 21 consecutive hot nights that started from 9 July, both the highest on record.
Read more: The Year's Weather – 2022
A trough of low pressure associated with the remnant of tropical cyclone Haikui brought torrential rain to Hong Kong from 7 to 8 September 2023. The Hong Kong Observatory headquarters registered 158.1 mm of rainfall from 11 p.m. to midnight, the highest hourly rainfall on record. Flash floods and landslides affected many parts of the territory, causing widespread traffic disruption and damage to infrastructures. The Government made the first-ever extreme conditions announcement amidst of torrential rain and flooding.
(Photo: CRHK News)
A waterspout briefly appeared over the seas off Hung Hom before 12:30 pm on 28 September 2024, the first occurrence over Victoria Harbour according to reports received by the Hong Kong Observatory since 1959.
Read more: Waterspout
(Photo: Kathie Wong)
2024 was the warmest year in Hong Kong on record with an annual mean temperature of 24.8 degrees, 1.3 degrees above the 1991-2020 climatological normal of 23.5 degrees.
Read more: The Year's Weather – 2024
The ferocious strikes of Typhoon Wipha and Super Typhoon Ragasa to Hong Kong respectively in July and September 2025 necessitated the issuance of the Hurricane Signal No. 10 twice in a year, tying the record of issuing the highest tropical cyclone warning signal twice in the same year since 1964.
(Photo: Chong Coco, Eric Wong, Kwok Yung Chan)
The outbreaks of heavy rain from late July to mid-August necessitated the issuance of the black rainstorm warnings for five times, including the three black rainstorm warnings in four days from 2 to 5 August. The Hong Kong Observatory registered a record-breaking rainfall of 368.9 mm on 5 August, the highest daily rainfall on record for August.
Read more: The Weather of July 2025; The Weather of August 2025
(Photo: Matthew Wong)
14 tropical cyclones necessitated the issuance of the tropical cyclone warning signal by the Observatory in 2025, the highest annual number since 1946.
Read more: The Year’s Weather 2025
"Worldwide" Category
Extreme rainfall affected Henan, China during 17-21 July 2021. The area near Zhengzhou was most severely hit, receiving 201.9 mm of rainfall in one hour and 382 mm in 6 hours. Flash floods in the city resulted in 380 reported deaths or missing persons, and economic losses of US$ 17.7 billion.
Further Reading: WMO State of the Global Climate 2021 (p. 27)
(Photo: Agence France-Presse via Getty Images)
In mid-February 2021, extreme cold waves affected many states in the United States. The state of Texas was most severely impacted, with some places experiencing freezing temperatures for up to 9 consecutive days. Temperatures in Dallas and Oklahoma City dropped to −18.9 °C and -25.6 °C respectively. At least 226 deaths were reported across the United States. It is the costliest winter storm on record for the United States, with an estimated economic loss of US$ 24 billion.
Further Reading: WMO State of the Global Climate 2021 (p. 25)
Pakistan experienced devastating floods during the 2022 monsoon season. Satellite data indicated that about 9% of Pakistan was flooded at some stage in August 2022. Over 1,700 deaths were reported, and more than 33 million people were affected. The economic losses were assessed at US$30 billion.
Further Reading: WMO State of the Global Climate 2022 (p. 28-29)
Numerous heatwaves affected Europe in the summer of 2022. Thousands of heat-related deaths were reported in Spain, Germany, the United Kingdom, France, and Portugal. On 19 July 2022, the United Kingdom recorded an extreme high temperature exceeding 40°C for the first time.
Further Reading: WMO State of the Global Climate 2022 (p. 24)
In the summer of 2022, central and eastern China experienced widespread high temperatures for 79 consecutive days. Nationwide, 60% and 70% of weather stations recorded temperatures higher than 37°C and 35°C, respectively. In Beibei, Chongqing, the maximum temperature reached 45°C on two consecutive days. High temperatures and low precipitation condition persistently affected the Yangtze River Basin, resulting in severe drought. Summer and autumn rainfall observations in the middle and lower reaches of the Yangtze River were 33% and 22% below normal, respectively. The prolonged high temperatures and drought brought economic losses exceeding RMB 40 billion.
Further Reading: China Climate Bulletin (2022) (p. 16,31,54)
Super typhoon Doksuri brought substantial damage to the Philippines and China in 2023. According to press reports, Doksuri left at least 25 deaths in the Philippines, with over 2.45 million people affected and economic loss exceeding PHP 5.4 billion. In East China and South China, around 2.95 million people were affected, with economic loss exceeding RMB 14.9 billion. The remnant of Doksuri also brought torrential rain to Beijing-Tianjin-Hebei region and Northeast China, resulting in over 150 deaths or missing, over 6.7 million people affected. The economic losses exceeded RMB160 billion.
Further Reading: Super Typhoon Doksuri (2305): 20 to 29 July 2023
(Photo: Basilio Sepe/ZUMA Press Wire/Shutterstock)
Mediterranean cyclone ‘Storm Daniel’ brought extreme rainfall and flooding to Greece, Bulgaria, and Türkiye, and Spain in early September 2023. In Greece, Zagora Pelion recorded rainfall as high as 759.6 mm on 5 September 2023. Storm Daniel impacted north-eastern Libya on 10 and 11 September 2023. Catastrophic flooding, with two dam failures in Libya, resulted in over 4,700 deaths and 8,000 missing people.
Further Reading: WMO Significant Weather & Climate Events 2023 (p. 4,14)
The annual average global temperature of 2024 was about 1.55℃ above pre-industrial (1850-1900) levels, marking 2024 as the first year to exceed the 1.5 ℃ level.
Further Reading: WMO State of the Global Climate 2024 (p. 3)
Super typhoon Yagi is the second strongest tropical cyclone in the South China Sea since the Observatory’s records began in 1950, on par with Super Typhoon Saola in 2023 and Super Typhoon Ragasa in 2025. The maximum sustained wind of Yagi was estimated at 230 km/h. Yagi and its remnant brought significant casualties and substantial damage to the Philippines, China, Lao PDR, Thailand, Myanmar, with Vietnam most severely affected. Yagi was the strongest tropical cyclone to make landfall in Vietnam in the last 30 years. There were at least 323 deaths, 22 missing and 1,978 injuries in Vietnam. More than 3.6 million people were affected, and economic loss exceeded VND 81 trillion.
Further Reading: TROPICAL CYCLONES IN 2024 (p. 73-92)
Senyar is a rare tropical cyclone that formed near the equator. It is also the first tropical cyclone to form in the Strait of Malacca in 135 years. In late November 2025, Senyar brought heavy rain, widespread flooding and landslides in Indonesia, Thailand, and Malaysia, affecting millions of people. As of 1 December, at least 604 deaths were reported in Indonesia and 177 in Thailand.