The Year's Weather

It was the wettest year since records began in 1884. Rainfall at the Hong
Kong Observatory amounted to 3 343.0 millimetres, 51 per cent above
normal and exceeding the previous record set in 1982. Over 70 per cent
of the rain fell in June, July and August. The extreme rainfall coincided
with an exceptionally strong E1 Ni隳 event in the equatorial Pacific. The
first tropical cyclone to affect Hong Kong did not come until the last day
of July, which was the latest in any year on record. The passage of
Typhoon Victor on August 2 necessitated the hoisting of the Increasing
Gale or Storm Signal No. 9, which was the highest warning signal since
Typhoon Ellen in 1983. The year's total duration of bright sunshine of
1 558.2 hours was the shortest recorded. The annual mean temperature
was 23.4 degrees, making 1997 the fourth-warmest year on record.

January was warmer and wetter than normal. The monthly mean
temperature of 16.7 degrees and total rainfall of 44.6 millimetres were
0.9 degrees and 21.2 millimetres higher than the respective averages.

The wet weather continued into February. The monthly rainfall totalled
111.7 millimetres which was 63.7 millimetres above normal.

Sunnier and warmer weather was observed in March and the total
sunshine duration amounted to 129.3 hours, 32.9 hours more than
normal. As a result, the monthly mean temperature reached 20.1 degrees,
the seventh-highest for March.

Cloudy conditions prevailed for most of April. The total bright sunshine
duration was only 73.6 hours, the tenth-lowest April record. The month
was also characterised by misty weather.

The weather in May was typical of the season in terms of precipitation.
Heavy rain occurred on May 8, necessitating the issuance of the first
Rainstorm Red Warning and Landslip Warning in the year.

Active troughs of low pressure brought a total rainfall of 783.6 millimetres
in June making it the seventh-wettest June on record. There were four
days with rainfall exceeding 100 millimetres recorded at the Observatory.

Exceptionally heavy rain associated with low pressure troughs continued
in July. The month's total rainfall of 746.0 millimetres made it the
fourth-highest for the month of July and the accumulated rainfall since
January 1 of 2 154.7 millimetres was 64 per cent above normal. A
Rainstorm Black Warning was issued on July 1 and Rainstorm Red
Warnings were required on the first three days of the month. Landslip and
Flood Warnings were also issued on two and eight occasions respectively.
Furthermore, the month's total bright sunshine duration of 125.1 hours
was the lowest on record. Tropical Cyclones came unusually late. The
first Tropical Cyclone Warning Signal of the year was hoisted on the last
day of the month due to the approach of Typhoon Victor. It was the
latest first tropical cyclone on record.

The approach of Typhoon Victor in the late afternoon on August 2
necessitated the hoisting of the Increasing Gale or Storm Signal No. 9,
the highest tropical cyclone warning signal since Typhoon Ellen in 1983.
Victor then weakened into a Severe Tropical Storm, but it still brought
cyclonic, storm-force winds before it made landfall over the western part
of Hong Kong that evening. During the passage of Victor, a man was
drowned near Stanley as he tried to rescue two people swept away by
high seas. About 60 people were injured in other storm-related incidents.
Torrential rain and thunderstorms caused three reported cases of landslips
and 20 of flooding. In late August, Typhoon Zita brought more heavy
rain to Hong Kong. A total of 829.0 millimetres of rainfall was recorded,
making this August the fourth-wettest on record.

September was cooler than normal and the mean temperature of 26.4
degrees was the eighth-lowest for the month. With no tropical cyclones
in Hong Kong's vicinity, the monthly mean pressure reached 1 012.1
hetopascals, the highest on record for September.

Rainfall in October amounted to only 112.8 millimetres or 32 millimetres
below average. However, the accumulated rainfall since January 1 of
3 329.4 millimetres was 55 per cent above the normal figure, surpassing
the previous record maximum annual rainfall of 3 247.5 millimetres set in
1982.

A weak north-east monsoon coupled with an unseasonal southerly
airstream gave rise to the warmest November on record. The mean
temperature of 23.1 degrees equalled the previous record set in 1966.
The mean minimum temperature of 21.2 degrees ranked highest for
November.

December was also warmer than normal with a mean temperature of
18.9 degrees, the seventh-highest for the month. However, the total
bright sunshine duration of 100.4 hours was the fourth-lowest for
December.

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