The Year's Weather - 2005
Weatherwise, 2005 was an eventful year globally speaking. Most notably, there were severe drought in parts of Africa, western Europe and Australia, record-breaking heavy rain in India, and an extremely active hurricane season in northern Atlantic. Locally in Hong Kong, 2005 was the third wettest year on record, mostly due to a very active southwest monsoon in June and August bringing in plenty of moisture. The total rainfall of 3214.5 millimetres was 45.2 percent above normal. June 2005 was the 4th wettest since records began in 1884, and August 2005 the 2nd wettest. The rainfall in these two months alone amounted to 1865.2 mm, about 84 percent of the normal annual rainfall.
While an unprecedented number of 27 named storms occurred in northern Atlantic against a normal of about 10, the year 2005 fell in a period of low tropical cyclone activity in the western North Pacific and the South China Sea, where only 26 tropical cyclones formed in the year, compared with the normal of 31. Three tropical cyclones affected Hong Kong in 2005, roughly half the normal figure. The first tropical cyclone warning signal of the year was issued on 12 August, the latest in post-war years.
2005 was also a hazy year. For 22.1 percent of the time, reduced visibility of 8 kilometres or below was observed at the Hong Kong International Airport. Despite a very wet June and August, below normal rainfall and hence a lack of washout processes was recorded in many other months, contributing to more frequent occurrence of haze.
January was drier than normal. With haze occurring on most of the days in the month, the number of hours of reduced visibility observed at the Hong Kong International Airport reached 476 hours.
February was gloomier and more humid than usual. The monthly mean relative humidity of 86 percent was the fourth highest for February.
March and April were drier than usual.
With the monsoon trough lingering near the south China coast, the weather of May was marked by heavy rain, active thunderstorms and severe squalls. The Amber Rainstorm Warning was issued seven times in the month, a new record for May since the warning system was introduced in 1998. During a rainstorm on 9 May severe gusts with speed reaching 135 kilometres per hour toppled stacked containers at container terminals in Kwai Chung and Tsing Yi, resulting in one death and two other injured. There were also over 100 reports of fallen trees and scaffoldings in different parts of the territory.
Very wet weather continued in June. A total of 893.9 millimetres of rainfall was recorded, more than double the normal monthly figure of 376 millimetres. The first Red Rainstorm Warning of the year was also issued during the torrential rain on 24 June.
July was warmer and sunnier than normal. There were reports of hail in Tsing Yi on 21 July amidst severe squally thunderstorms.
August was much wetter than normal. The total rainfall was 971.3 millimetres, almost two and a half times the normal figure of 391.4 millimetres. The Standby Tropical Cyclone Warning Signal No. 1 was issued for the first time in the year on the approach of Severe Tropical Storm Sanvu.
September was marked by the hazy weather associated with the relatively weak northeast monsoon and distant tropical cyclones east of Hong Kong. The number of hours of reduced visibility observed at the Hong Kong International Airport reached 195 hours in the month. The Standby Signal No.1 was issued during the approach of Tropical Storm Vicente. Typhoon Damrey necessitated the issuance of the first and only Strong Wind Signal No. 3 in the year.
October and November were drier and much warmer than normal. The mean minimum temperature of November was 21.4 degrees, the same as the record high set in 1998.
December was cooler and drier than normal. Frost was reported in the New Territories on 23 December.
 Month |
Mean Pressure (hPa) |
Air Temperature | Mean Dew Point Temperature (deg. C) |
Mean Relative Humidity (%) |
Mean Amount of Cloud (%) |
Total Rainfall (mm) | ||
|---|---|---|---|---|---|---|---|---|
Mean Daily Maximum (deg. C) |
Mean (deg. C) |
Mean Daily Minimum (deg. C) | ||||||
| January | 1019.6 | 17.9 | 15.9 | 14.2 | 11.3 | 75 | 63 | 5.9 |
| February | 1017.9 | 18.3 | 16.5 | 14.8 | 14.0 | 86 | 91 | 19.2 |
| March | 1018.7 | 19.7 | 17.4 | 15.2 | 13.7 | 80 | 76 | 52.6 |
| April | 1014.1 | 25.4 | 23.1 | 21.3 | 19.9 | 83 | 79 | 32.3 |
| May | 1007.9 | 28.8 | 27.0 | 25.3 | 24.1 | 85 | 82 | 508.6 |
| June | 1004.6 | 29.7 | 27.8 | 25.9 | 24.9 | 85 | 85 | 893.9 |
| July | 1006.4 | 31.8 | 29.1 | 26.9 | 25.1 | 80 | 59 | 360.4 |
| August | 1004.8 | 30.2 | 28.0 | 26.3 | 25.2 | 85 | 74 | 971.3 |
| September | 1009.2 | 30.4 | 28.2 | 26.5 | 24.4 | 81 | 69 | 352.6 |
| October | 1014.9 | 28.3 | 26.2 | 24.4 | 20.6 | 72 | 57 | 6.6 |
| November | 1016.6 | 25.0 | 23.0 | 21.4 | 18.6 | 77 | 55 | 1.6 |
| December | 1021.2 | 19.1 | 17.0 | 15.0 | 9.7 | 64 | 59 | 9.5 |
| Mean/Total | 1013.0 | 25.4 | 23.3 | 21.4 | 19.3 | 79 | 71 | 3214.5 |
| Normal* | 1012.9 | 25.7 | 23.0 | 20.9 | 18.6 | 77 | 65 | 2214.3 |
| Station | Hong Kong Observatory | |||||||
Month |
Number of hours of Reduced Visibility# (hours) |
Total Bright Sunshine (hours) |
Mean Daily Global Solar Radiation (MJ/m2) |
Total Evaporation (mm) |
Prevailing Wind Direction (degrees) |
Mean Wind Speed (km/h) |
|---|---|---|---|---|---|---|
| January | 476 | 141.7 | 9.63 | 64.1 | 070 | 21.6 |
| February | 131 | 34.4 | 6.02 | 35.1 | 040 | 24.7 |
| March | 153 | 95.3 | 9.86 | 67.4 | 060 | 24.7 |
| April | 198 | 104.3 | 11.40 | 77.8 | 080 | 17.6 |
| May | 14 | 87.6 | 10.96 | 92.4 | 210 | 20.8 |
| June | 9 | 82.5 | 10.81 | 92.0 | 230 | 24.4 |
| July | 21 | 244.5 | 18.49 | 165.8 | 240 | 18.0 |
| August | 42 | 170.2 | 14.51 | 134.5 | 240 | 23.1 |
| September | 195 | 180.4 | 14.32 | 127.5 | 090 | 23.4 |
| October | 205 | 221.7 | 14.63 | 135.0 | 080 | 24.9 |
| November | 219 | 210.0 | 12.53 | 93.1 | 080 | 22.9 |
| December | 276 | 179.7 | 11.41 | 99.4 | 020 | 27.7 |
| Mean/Total | 1939 | 1752.3 | 12.05 | 1184.1 | 080 | 22.8 |
| Normal* | 1140.0 § | 1948.1 | 14.46 | 1528.8 | 080 | 22.6 |
| Station | Hong Kong International Aiport |
King's Park | Waglan Island^ | |||
The minimum pressure recorded at the Hong Kong Observatory was 995.6 hectopascals at 1651 HKT on 6 August. The maximum air temperature recorded at the Hong Kong Observatory was 35.4 degrees Celsius at 1703 HKT on 19 July. The minimum air temperature recorded at the Hong Kong Observatory was 6.4 degrees Celsius at 0751 HKT on 1 January. The maximum gust peak speed recorded at Waglan Island was 108 kilometres per hour from 070 degrees at 1631 HKT on 24 September. The maximum instantaneous rate of rainfall recorded at King's Park was 309 millimetres per hour at 1140 HKT on 21 June.
# Reduced visibility refers to visibility below 8 kilometres when there is no fog, mist, or precipitation. -The visibility readings at the Hong Kong International Airport are based on hourly observations by professional meteorological observers in 2004 and before, and average readings over the 10-minute period before the clock hour of the visibility meter near the middle of the south runway from 2005 onwards. The change of the data source in 2005 is an improvement of the visibility assessment using instrumented observations following the international trend. -Before 10 October 2007, the number of hours of reduced visibility at the Hong Kong International Airport in 2005 and thereafter displayed in this web page was based on hourly visibility observations by professional meteorological observers. Since 10 October 2007, the data have been revised using the average visibility readings over the 10-minute period before the clock hour, as recorded by the visibility meter near the middle of the south runway. * 1961-1990 Climatological Normal, unless otherwise specified § 1997-2004 Mean value ^ In case the data are not available from Waglan Island, observations of Cheung Chau or other nearby weather stations will be incorporated in computing the Prevailing Wind Direction and Mean Wind Speed |