Appendix F Meteorological Data

November 2014

The weather of November 2014 was overall cloudier yet warmer than usual. The mean temperature for the month was 22.6 degrees, 0.8 degrees above the normal figure of 21.8 degrees. Despite more clouds and less sunshine, the total rainfall of 31.1 millimetres recorded in the month was about 17 percent below the normal figure of 37.6 millimetres. The accumulated rainfall since 1 January was 2593.6 millimetres, about 9 percent above the normal of 2371.7 millimetres for the same period.

December 2014

Affected by frequent replenishments of the winter monsoon, the weather of December 2014 was cooler than normal, with spells of cloudy and rainy weather. The mean temperature for the month was 16.3 degrees, 1.6 degrees below the normal figure of 17.9 degrees. The total duration of bright sunshine in the month was 115.3 hours, 33 percent below the normal figure of 172.2 hours. The monthly total rainfall was 44.7 millimetres, about 67 percent above the normal figure of 26.8 millimetres. The annual rainfall of 2014 was 2638.3 millimetres, about 10 percent above the normal of 2398.5 millimetres.  

January 2015

With the northeast monsoon bringing dry continental air mass to the south China coast during the month, the weather of January 2015 was sunnier than usual.  The total duration of sunshine in the month was 198.8 hours, 39 percent above the normal figure of 143.0 hours.  The monthly mean amount of cloud was 45 percent, against a normal figure of 61 percent.  As a result of the rain on 12 and 13 January, the monthly total rainfall of 41.7 millimetres was 69 percent above the January normal of 24.7 millimetres.  Overall, the mean temperature of the month was 16.4 degrees, only 0.1 degree above normal.

February 2015

February 2015 was a month of two halves : mostly fine and dry in the first half, and generally cloudy and humid in the second half.  Overall, it was warmer than usual with a monthly mean temperature of 17.5 degrees compared to the normal figure of 16.8 degrees.  The monthly rainfall was 32.0 millimetres, less than 60 percent of the normal figure of 54.4 millimetres.  The accumulated rainfall of 73.7 millimetres in the first two months of the year was about 7 percent below the normal figure of 78.9 millimetres for the same period.

March 2015

With a maritime airstream dominating over the coast of Guangdong during the latter half of the month, the weather of Hong Kong in March 2015 was warmer than usual.  The monthly mean temperature was 19.9 degrees, 0.8 degrees higher than the normal figure of 19.1 degrees.  The total rainfall in the month was 28.4 millimetres, only about 35 percent of the normal figure of 82.2 millimetres. The accumulated rainfall of 102.1 millimetres since 1 January was about 37 percent below the normal figure of 161.3 millimetres for the same period.

April 2015

April 2015 was characterized by sunny, warm and relative dry weather, in particular during the second half of the month.  Overall, the total duration of sunshine in April 2015 was 159.2 hours, 57.5 hours above the normal figure of 101.7 hours.  The mean temperature of the month was 23.6 degrees, 1.0 degree higher than the normal figure of 22.6 degrees.  The monthly mean relative humidity was 77 percent, the third lowest for April since 1961.  

May 2015

May 2015 was the fourth hottest May since records began in 1884. Its monthly mean temperature of 27.5 degrees was 1.6 degrees higher than the normal figure of 25.9 degrees. Affected by active troughs of low pressure in the second half of the month, May 2015 was actually cloudier than usual and rather rainy as well. Bright sunshine during the month amounted to 93.5 hours only, about 33 percent below the normal figure of 140.4 hours, the seventh lowest for May on record. The monthly total rainfall was 513.0 millimetres, a surplus of 68 percent against the normal figure of 304.7 millimetres. The accumulated rainfall of 679.6 millimetres since 1 January was about 6 percent above the normal figure of 640.8 millimetres for the same period.

June 2015

June 2015 was the hottest June in Hong Kong since records began in 1884.  The monthly mean temperature of 29.7 degrees was 1.8 degrees above the normal figure of 27.9 degrees and broke the previous record of 29.0 degrees set in 2014 by a wide margin of 0.7 degree.  Both the monthly mean minimum temperature of 27.7 degrees and the monthly mean maximum temperature of 32.3 degrees ranked the highest for June.  The extremely hot weather in June 2015 in Hong Kong was partly attributed to the westward extension of the subtropical ridge of high pressure from the western North Pacific to southern China during the month.  The prevailing southerly flow and the above-normal sea surface temperature over the northern part of the South China Sea also contributed to the sweltering weather.

July 2015

July 2015 was warmer and cloudier than usual. The mean temperature in the month was 29.1 degrees, 0.3 degrees above the normal figure of 28.8 degrees. The monthly mean cloud amount of 75 percent was 6 percent above the normal figure of 69 percent. With the increase in cloudiness, the total sunshine duration recorded in July 2015 was only 164.9 hours, about 22 percent below normal. The month was also wetter than usual with a monthly total rainfall of 406.2 millimetres, 8 percent above the normal figure of 376.5 millimetres. The accumulated rainfall of 1387.9 millimetres since 1 January was about 6 percent below the normal figure of 1473.3 millimetres for the same period.

August 2015

August 2015 was hotter and drier than usual. The mean temperature in the month was 29.3 degrees, 0.7 degree above the normal figure of 28.6 degrees and the seventh highest for August on record. The monthly total rainfall recorded in August 2015 was 143.3 millimetres, only about one-third of the normal figure of 432.2 millimetres. The accumulated rainfall of 1531.2 millimetres since 1 January was about 20 percent below the normal figure of 1905.5 millimetres for the same period.

September 2015

September 2015 was marked by sunny and warm weather with below normal rainfall. The monthly mean temperature of 28.4 degrees was the seventh highest for September on record and 0.7 degrees above the normal figure of 27.7 degrees. With no tropical cyclone affecting Hong Kong and necessitating the issuance of tropical cyclone warning signals in August and September, a record since 1946, the total rainfall in September was only 87.9 millimetres, a deficit of about 73 percent comparing to the normal figure of 327.6 millimetres. The accumulated rainfall of 1619.1 millimetres since 1 January was about 27 percent below the normal figure of 2233.1 millimetres for the same period.

October 2015

The weather of October 2015 was warmer than usual. The monthly mean temperature of 26.0 degrees was 0.5 degrees above the normal figure of 25.5 degrees. The month was also wetter than usual, mainly as a result of heavy rain brought by tropical cyclone Mujigae during the first week of the month. A total of 168.3 millimetres of rainfall was recorded of the month, about 67 percent above the normal figure of 100.9 millimetres. However, the accumulated rainfall of 1787.4 millimetres since 1 January was still about 23 percent below the normal figure of 2334.0 millimetres for the same period.