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Globally, despite the cooling influence of a weak-to-moderate La Nina at the beginning of the year, 2012 is still an unusually warm year in many parts of the world. The global average temperature from January to November 2012 is likely to rank among the top ten warmest for the same period. Moreover, notable extreme weather events were observed worldwide in 2012, including major heat waves in the United States and Europe; the cold spell in the Eurasian continent; severe drought in the continental United States, the northern part of Mexico, western Russia, southeast Europe, northern Brazil and the Yunnan and Sichuan provinces of China; extreme flooding in parts of Africa and Pakistan; and tropical cyclone induced torrential rain in the Philippines, Japan, Korean Peninsula and the northeastern part of contiguous United States. Over the Arctic, the sea ice extent also reached a new record low in September 2012.
In Hong Kong, 2012 started with significantly colder than normal weather in January and February which is mainly due to the stronger northeast monsoon over southern China usually in the presence of La Nina. However, with La Nina fading out in spring, the below-normal temperature in the beginning of the year was compensated by the exceptionally warm weather in April, May and August in 2012. Overall, the average temperature of 2012 was 23.4 degrees, 0.1 degrees above the 1981-2010 normal (Note 1) figure of 23.3 degrees (0.4 degrees above the 1961-1990 normal figure of 23.0 degrees when we consider an earlier timeframe) and ranking the 12th highest since record began in 1885. For extreme temperatures, there were 21 Very Hot Days (Note 2), 23 Hot Nights (Note 3) and 21 Cold Days (Note 4) in 2012, about 11, 5 and 4 days more than the 1981-2010 normal figures respectively. The maximum temperature recorded at the Hong Kong Observatory in 2012 was 34.5 degrees on August 28. During the passage of an intense cold surge of the winter monsoon, the minimum temperature of the year of 7.1 degrees was recorded on December 31. This was also the third coldest New Year's Eve on record.
The year 2012 was drier than usual. With well below normal rainfall in June and August, the annual rainfall of 1924.7 millimetres was about 20 per cent below the 1981-2010 normal (about 13 per cent below the 1961-1990 normal). There were only two red rainstorm warnings issued by the Hong Kong Observatory in 2012, about half of the average number of red rainstorm warnings in a year since the Rainstorm Warning System commenced operation in 1992. There was no black rainstorm warning issued in the year. The number of days with thunderstorms reported in Hong Kong was 37 days in 2012, close to the 1981-2010 normal.
It was exceptionally gloomy in 2012, particularly in the first two months and the last two months of the year. The annual total duration of bright sunshine of 1551.2 hours was the lowest since record began in 1885.
A total of 27 tropical cyclones occurred over the western North Pacific and the South China Sea in 2012, slightly less than the normal annual figure of around 29. 15 of the tropical cyclones reached typhoon intensity (Note 5) or above during the year, close to the normal annual figure. In Hong Kong, five tropical cyclones necessitated the issuance of local tropical cyclone warning signals, close to the long term average of about six in a year. The Hurricane Signal No. 10 was issued during the passage of Vicente in July, while the No. 8 Gale or Storm Signal was issued during the passages of Doksuri and Kai-tak respectively in June and August.
Detailed descriptions of the weather for individual months are available in the Monthly Weather Summary webpage:¡@www.hko.gov.hk/wxinfo/pastwx/mws.htm .
A detailed version of the Year's Weather for 2012 with significant weather events in Hong Kong is available at www.hko.gov.hk/wxinfo/pastwx/ywx.htm .
Note 1: Climatological normals for the reference period of 1961-1990, 1971-2000 and 1981-2010 are available at www.weather.gov.hk/cis/normal_e.htm . Climatological normals of 1981-2010 are referenced in the text unless otherwise stated.
Note 2: "Very Hot Day" refers to the condition with the daily maximum temperature equal to or higher than 33.0 degrees.
Note 3: "Hot Night" refers to the condition with the daily minimum temperature equal to or higher than 28.0 degrees.
Note 4: "Cold Day" refers to the condition with the daily minimum temperature equal to or lower than 12.0 degrees.
Note 5: Information on the classification of tropical cyclones is available at www.hko.gov.hk/informtc/class.htm.
Ends/Tuesday, January 8, 2013
Issued at HKT 20:33
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