GEOGRAPHY AND CLIMATE
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Although there were more than the usual number of thunder- storms and days with rain in May, the total rainfall for the month was still about 10 per cent below normal. Most of the rain was due to an active trough which developed along the South China coast on May 18 and persisted until the middle of June. The trough produced heavy showers and thunderstorms on June 12 and 13, causing landslides and flooding. Altogether 326.2 mm (12.84 inches) of rain were recorded during these two days and the amount registered at the Royal Observatory between 3.00 and 4.00 a.m. on June 13 was 100 mm (3.94 inches) which was the third highest hourly rainfall on record.
July was a very hot and dry month. The mean temperature of 29.3°C and the maximum temperature of 35.7°C were both the second highest on record while the mean relative humidity of 78 per cent was the second lowest ever recorded in July. Almost 90 per cent of the total rainfall fell in the first five days of the month.
A total of 14 tropical cyclones was reported over the western Pacific and South China Sea during July to September and six came close enough to Hong Kong to necessitate the hoisting of local storm signals.
三
Typhoon Nadine formed as a tropical depression over the Pacific about 500 miles east-north-east of Manila on July 21. During the following four days the storm followed a somewhat erratic course but with a general tendency towards the north-west. After crossing the southern tip of Taiwan on July 25, it began to turn onto a westerly course' towards the South China coast. However, on July 27, it weakened into a tropical storm and re- curved towards the north-east giving rise to only a few hours of strong winds in some exposed places in the Colony.
Severe tropical storm Rose developed on August 10 about 270 miles north-east of Manila and moved rapidly west-north-west across northern Luzon. During the evening of August 11, Rose passed about 240 miles south of Hong Kong and moved towards Hainan Island. Strong winds were experienced in some exposed places during the passage of the storm.
Typhoon Shirley was one of the very few tropical cyclones which passed directly over the Royal Observatory. The storm