The Weather of June 2014

With the monthly mean temperature reaching 29.0 degrees, June 2014 was the hottest June in Hong Kong since records began in 1884. The monthly mean minimum temperature of 27.0 degrees and maximum temperature of 31.5 degrees were respectively one of the second and the third highest for June. Such high temperatures were attained despite the facts that sunshine duration and rainfall for the month were not far from normal. The total rainfall of the month was 436.6 millimetres, about 4 percent below the normal figures of 456.1 millimetres. The accumulated rainfall since 1 January of 1503.4 millimetres was about 37 percent above the normal figure of 1096.9 millimetres for the same period.

Under the dominance of an anticyclone aloft, the weather in Hong Kong was mainly fine and very hot for the first two days of the month. Affected by a trough of low pressure, it turned cloudy with some showers and isolated thunderstorms on 3 June. With the trough of low pressure pushed back towards the mainland areas of Guangdong, fine and hot weather returned on 4 June apart from a few morning showers. However, the lingering presence of the trough continued to bring a mixture of sunshine and thundery showers to the territory in the next four days.

With the setting in of a fresh easterly airstream on 9 June, showers and thunderstorms gradually eased off and there were sunny intervals during the days on 10 and 11 June. Under the influence of a dry continental airstream, local weather remained mostly fine and dry for the ensuing three days.

    While Hong Kong experienced a very hot day on 14 June, a tropical depression formed over the northeastern part of the South China Sea and intensified into a tropical storm named Hagibis. Tracking generally northwards, Hagibis made landfall near Shantou in the afternoon on 15 June and weakened into a tropical depression that night. Affected by the rainbands of Hagibis, local weather was cloudy with some showers on 15 June.

    A southwest monsoon then maintained generally hot weather with sunny periods and thundery showers over the next five days. As another trough of low pressure lingered along the south China coast, the weather in Hong Kong became even more unsettled with occasional heavy showers and squally thunderstorms from 21 to 25 June. The showers were particularly heavy on the morning of 22 June. Rainfall exceeded 70 millimetres over widespread areas and more than 150 millimetres were recorded at Lamma Island, Cheung Chau, the eastern part of Lantau Island and the western part of Hong Kong Island.

    With an anticyclone aloft establishing over southern China, sunny and very hot weather returned from 26 to 28 June. Temperatures recorded at the Hong Kong Observatory rose to a maximum of 33.7 degrees on 27 June, the highest of the month.   Affected by a broad trough of low pressure over the coast of Guangdong and the northern part of the South China Sea, there were sunny periods with a few showers and isolated thunderstorms on the last two days of the month.

Two tropical cyclones occurred over the South China Sea and the western North Pacific in the month.

Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.5. Monthly meteorological figures and departures from normal for June are tabulated in Table 2.

Table 1.1 Tropical Cyclone Warning Signals

Name of Tropical Cyclone	Signal Number	Beginning Time		Ending Time
Name of Tropical Cyclone	Signal Number	Day/Month	HKT	Day/Month	HKT
HAGIBIS	1	14 / 6	1740	15 / 6	1320

Table 1.2 Rainstorm Warning Signals

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Amber	8 / 6	2135	8 / 6	2200
Red	8 / 6	2200	8 / 6	2310
Amber	8 / 6	2310	8 / 6	2345
Amber	21 / 6	0830	21 / 6	1050
Amber	22 / 6	0120	22 / 6	0205
Red	22 / 6	0205	22 / 6	0505
Amber	22 / 6	0505	22 / 6	0625

Table 1.3 Thunderstorm Warning

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
3 / 6	1744	3 / 6	1845
5 / 6	0842	5 / 6	0945
5 / 6	1115	5 / 6	1640
6 / 6	0600	6 / 6	0830
6 / 6	0925	6 / 6	1430
7 / 6	1255	7 / 6	1400
8 / 6	1344	8 / 6	1515
8 / 6	1946	9 / 6	0345
16 / 6	0245	16 / 6	0600
17 / 6	0715	17 / 6	1015
17 / 6	1135	17 / 6	1345
18 / 6	0310	18 / 6	0845
19 / 6	0238	19 / 6	0845
19 / 6	0910	19 / 6	1130
20 / 6	0215	20 / 6	0515
20 / 6	0550	20 / 6	1430
20 / 6	1505	20 / 6	1615
20 / 6	1800	20 / 6	1900
20 / 6	2220	21 / 6	1200
21 / 6	1925	21 / 6	2230
21 / 6	2310	22 / 6	1000
23 / 6	0440	23 / 6	0800
23 / 6	0845	23 / 6	1200
23 / 6	2140	24 / 6	0300
24 / 6	0400	24 / 6	0730
24 / 6	0900	24 / 6	1430
25 / 6	0350	25 / 6	1530
25 / 6	1555	25 / 6	1700
29 / 6	2139	29 / 6	2315
30 / 6	1145	30 / 6	1630

Table 1.4 Fire Danger Warnings

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Red	13 / 6	1145	13 / 6	2035

Table 1.5 Very Hot Weather Warning

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
30 / 5	0645	2 / 6	1900
4 / 6	1015	4 / 6	1845
5 / 6	1020	5 / 6	1345
14 / 6	1220	14 / 6	1745
18 / 6	1300	18 / 6	1800
26 / 6	1330	28 / 6	1825

Table 2 Figures and Departures from Normal - June 2014

Meteorological Element	Figure of the Month	Departure from Normal*
Mean Daily Maximum Air Temperature	31.5 degrees C	1.3 degrees above normal
Mean Air Temperature	29.0 degrees C	1.1 degrees above normal
Mean Daily Minimum Air Temperature	27.0 degrees C	0.8 degree above normal
Mean Dew Point Temperature	25.0 degrees C	0.4 degree above normal
Mean Relative Humidity	80 %	2 % below normal
Mean Cloud Amount	77 %	normal
Total Rainfall	436.6 mm	19.5 mm below normal
Number of hours of Reduced VisibilityΔ	17 hours	2.6 hours below normal§
Total Bright Sunshine Duration	147.3 hours	1.2 hours above normal
Mean Daily Global Solar Radiation	15.78 Megajoule / square metre	1.59 Megajoule above normal
Total Evaporation	127.7 mm^	10.6 mm above normal

Remarks :	All measurements were made at the Hong Kong Observatory except sunshine, solar radiation and evaporation which were recorded at King's Park Meteorological Station and visibility which was observed at the Hong Kong International Airport.
Δ	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.
* Departure from 1981 - 2010 climatological normal, except for number of hours of reduced visibility
§ Departure from mean value between 1997 and 2013
^ Total for 28 days

daily values of selected meteorological elements for HK for June 2014

The percentile map of mean temperature of June 2014

Remarks :

Extremely high: above 95th percentile
Above normal: between 75th and 95th percentile
Normal: between 25th and 75th percentile
Below normal: between 5th and 25th percentile
Extremely low: below 5th percentile
Percentile and 5-day running average values are
computed based on the data from 1981 to 2010

Rainfall Map For June 2014 (isohyets are in millimetres)

Extract of Meteorological Observations in Hong Kong for June 2014