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A preliminary assessment of the global average temperature from January to November 2013 suggests that 2013 is likely to be among the 10 warmest years since global records began in 1850. Moreover, there were numerous significant weather events around the world in 2013, including heat waves in Australia, Austria, Pakistan and southern China; severe drought in Brazil, New Zealand, southern Africa and southern China; extreme rainfall and flooding in Queensland and New South Wales of Australia, Mozambique, Argentina, Alpine region of Europe, southern England, Poland, Czech Republic, Russia and India; heavy snow in the northern parts of the United Kingdom, the contiguous United States and the Middle East; Super Typhoon Usagi in southern China; Super Typhoon Haiyan in the Philippines; Very Severe Cyclonic Storm Phailin in India; and torrential rain induced by tropical cyclones in Mexico, Japan, the Philippines, Vietnam and Cambodia. With sea surface temperature over the central and equatorial Pacific remaining largely normal, there was no significant La Nina or El Nino development in 2013.
On the whole, the average temperature in Hong Kong in 2013 was 23.3 degrees, on par with the 1981-2010 normal (Note 1) (or 0.3 degrees above the 1961-1990 normal of 23.0 degrees). The year began with significantly warmer-than-normal weather in the first three months. In particular, under the influence of mild easterly maritime airstreams, the mean temperature of February and March was 1.9 degrees above normal and ranked the fifth highest on record for the same period. However, this warm anomaly was counter-balanced by the cooler weather in April, July and December with monthly mean temperatures 1.1, 0.8 and 1.8 degrees below normal respectively. Affected by the rainy and gloomier weather in July and August, there were only 10 Hot Nights (Note 2) in the year, about seven days below normal. Regarding extreme temperatures, there were 17 Very Hot Days (Note 3) in 2013, about seven days more than the 1981-2010 normal figure. The number of Cold Days (Note 4) in the year was 14 days, about three days below normal. In 2013, the maximum temperature recorded at the Hong Kong Observatory was 34.9 degrees on August 12, and the minimum temperature recorded was 9.2 degrees on December 18.
Associated with the heavy rain episodes in the unsettled and stormy summer months, 2013 was also a wet and thundery year. The annual total rainfall was 2847.3 millimetres, a surplus of about 19 per cent comparing to the 1981-2010 normal of 2398.5 millimetres (and about 29 per cent above the 1961-1990 normal), and the total number of days with thunderstorms reported at the Hong Kong Observatory was 53 days, the highest since records began in 1947, tied with the record set in 1997. A trough of low pressure brought torrential rain and intense thunderstorms to Hong Kong on May 22, necessitating the issuance of Black Rainstorm Warning by the Hong Kong Observatory, the first time since July 2010.
A total of 33 tropical cyclones occurred over the western North Pacific and the South China Sea in 2013, more than the long term (1961-2010) average of around 30. There were 14 tropical cyclones reaching typhoon intensity (Note 5) or above during the year, slightly below the long term average of about 15. In Hong Kong, seven tropical cyclones necessitated the issuance of local tropical cyclone warning signals, slightly higher than the long term average of about six in a year. The No. 8 Gale or Storm Signal was issued during the passage of Super Typhoons Utor and Usagi in August and September respectively, of which Usagi was also the most intense tropical cyclone affecting Hong Kong in 2013. Furthermore, Severe Typhoon Krosa was the first tropical cyclone that necessitated the issuance of tropical cyclone warning signals in November since 2006.
Detailed descriptions of the weather for individual months of 2013 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 2013 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: "Hot Night" refers to the condition with the daily minimum temperature equal to or higher than 28.0 degrees.
Note 3: "Very Hot Day" refers to the condition with the daily maximum temperature equal to or higher than 33.0 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/Wednesday, January 8, 2014
Issued at HKT 20:37
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