Introduction

In recent years, extreme weather such as intense cold surge, 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 is organising a public activity "2016-2020 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.

Voting period has ended. Thank you for your support. The results will be announced tentatively in late March 2021.

  1. 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.
  2. The voting period starts on 28 January, 2021 and ends at 23:59:59 on 28 February, 2021, based on the time of reception at the server of this website. Late submissions will not be entertained.
  3. Each participant can only vote once. If repetitive votes were found, the related voting records may be discarded.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. Each email address is eligible for winning souvenirs once only. The results of the campaign will be announced tentatively in late March 2021. Winners will also be notified via email afterwards.
  9. In case of any dispute, the decision of the Hong Kong Observatory shall be final.

"Hong Kong" Category

An Intense cold surge brought freezing weather to Hong Kong in late January 2016. A minimum temperature of 3.1 degrees was recorded at the Observatory on 24 January, the coldest in almost 60 years. Temperature at Tai Mo Shan even fell to a minimum of -6.0 degrees. Widespread frost, rime, icing, freezing rain and ice pellets were reported on high ground and in some parts of the New Territories.
Photo: Lam Miu Fong
The combined effect of tropical cyclone Sarika and the northeast monsoon brought heavy rain to Hong Kong on 19 October, 2016. Black Rainstorm Warning was issued for the first time in the month of October since the Rainstorm Warning System commenced its operation in 1992. The monthly rainfall in October 2016 was more than six times the October normal. The total rainfall for autumn (September to November) even exceeded 1,000 millimetres, the highest in record.
Photo: Drainage Services Department
Subsidence effect ahead of Super Typhoon Hato’s circulation brought oppressive heat to Hong Kong on 22 August, 2017. The maximum temperature at the Observatory that afternoon soared to 36.6 degrees, the highest since records began in 1884. Temperature at Yuen Long Wetland Park even reached 39.0 degrees, the highest ever recorded by an automatic weather station in Hong Kong.
Super Typhoon Hato hit Hong Kong on 23 August, 2017. No. 10 Hurricane Signal was in force for 5 hours. The storm surge raised the water level in Hong Kong generally by about one to two metres. Coinciding with the high water of the astronomical tide, the aggregated effect caused the water level in Victoria Harbour to reach a maximum of 3.57 mCD, resulting in the inundation of many low-lying areas in Hong Kong by sea water. At least 129 people were injured during the passage of Hato, with over 5,300 reports of fallen trees. Besides, five tropical cyclones necessitated the issuance of Tropical Cyclone Signal No.8 or above in 2017, tying the records in 1964 and 1999.
Photo: Charmaine Mok
It was exceptionally hot in Hong Kong in May 2018. The monthly mean temperature was 28.3 degrees, highest on record in May. There were 16 very hot days and 6 hot nights in that month, both breaking the records in May. Besides, the 15-day heat wave spanning from 17 May to 31 May also set the record of longest consecutive very hot days in May. Meanwhile, the accumulated rainfall recorded in the first five months of 2018 was merely 175.0 mm, a deficit of over 70 percent compared to the normal value and being the second lowest record for the same period since 1884.
Tropical Cyclone Bebinca exhibited an erratic movement and lingered over the seas off the coast of western Guangdong for several days. The tropical cyclone warning signal was in force for 132 hours, the third longest in the post-war era.
Super Typhoon Mangkhut hit Hong Kong directly on 16 September, 2018. It was the most destructive typhoon to Hong Kong since Ellen in 1983. The No. 10 Hurricane signal was in force for 10 hours. Mangkhut brought damaging winds and record-breaking storm surges to Hong Kong. Water level in Victoria Harbour reached a maximum of 3.88 mCD, the highest since Wanda in 1962. There were severe inundations by sea water in many coastal and low-lying areas. At least 458 people were injured, hundreds of vessels were stranded, sunk or seriously damaged. There were more than 60,000 reports of fallen trees, and electricity supply to over 40,000 households was interrupted.
Photo: H C Chan
2019 was the warmest year in Hong Kong since records began in 1884. Annual mean temperature were 24.5 degrees, 1.2 degrees above the 1981-2010 climatological normal. Eleven out of the twelve months of the year were warmer than normal. There was only one cold day in the entire year, the fewest on record. Besides, the 2018/19 winter (December to February) was also the warmest winter on record, with mean temperature, mean maximum temperature and mean minimum temperature all being highest on record.
Under the influence of a trough of low pressure, there were heavy showers and squally thunderstorms in Hong Kong on 6 June 2020, and the Black Rainstorm Warning was issued. 14,358 cloud-to-ground lightning strokes were detected in Hong Kong on that day, the second highest on record since the launch of the lightning location system in 2005.
The total number of very hot days (47 days), total number of hot nights (50 days), and the number of hot nights in a single month (July, 21 days) in 2020 are all the highest on records. Meanwhile, Hong Kong also experienced the hottest summer (June to August) in 2020 on record, with July being the hottest month since record began in 1884.

"Worldwide" Category

Much of southern Africa began the year of 2016 in severe drought, causing crop failures in many countries of the region. The World Food Programme estimated that 18.2 million people required emergency assistance.
The five-year average of 2016–2020 is the warmest on record since 1850.
Chart: UK Met Office / World Meteorological Organization
Floods caused by torrential rain killed more than 1,200 people in India, Bangladesh and Nepal in August 2017. More than 40 million people were affected.
A heatwave swept Japan in July 2018 with estimated death toll over 1,000. In the city of Kumagaya located near Tokyo, a maximum temperature of 41.1 degrees was recorded, the highest ever in the country.
Severe Typhoon Jebi swept across the eastern part of Shikoku, Osaka Bay and Kansai on 4 September 2018. It was then the strongest typhoon to hit Japan since 1993, with at least 11 people killed. The coastal regions of Osaka were severely flooded due to storm surge induced by Jebi. Kansai International Airport was once shut down entirely due to flooding.
(Photo: The Asahi Shimbun via Getty Images)
High temperature and drought contributed to destructive wildfires in many parts of Australia, and California in the United States in 2019 and 2020. Since September 2019, a series of massive bushfires across Australia burnt 21% of forests in the country and killed over 1 billion animals. The bushfire only came under control gradually in March 2020. The 2020 California wildfire season was characterised by record-setting wildfires, with nearly 10,000 fires burning over 17,000 sq. km of land.
Further Reading: Endless wildfires
The "plum rain" season over East Asia was extremely prolonged and active in 2020, causing over 300 deaths and economic losses of over US$10 billion. In particular, persistent rain over the Yangtze River catchment in June and July caused widespread flooding, while Japan and Korea were also severely flooded by the torrential rain.
(Satellite imagery: Himawari-8 Satellite of Japan Meteorological Agency)
Greenland lost a record high of 532 billion tonnes of ice in 2019. The average rate of loss was 1 million tonnes per minute, equivalent to 400 Olympic-sized swimming pools of ice per minute.
Temperature in the Arctic Siberian town of Verkhoyansk reached 38°C on 20 June 2020, setting a record for the highest temperature north of the Arctic Circle.
(Image: NASA)
The 2020 North Atlantic hurricane season was extremely active. There was a total of 30 named tropical cyclones in the year, more than twice of the normal number (11.3). The list of 21 names provided by the National Hurricane Center had been exhausted and Greek alphabet had to be used for the remaining tropical cyclones, first time since 2005.
(Satellite imagery: GOES-16 Satellite of NOAA)