TUESDAY, JANUARY 21, 1975
VIOLENT THUNDERSTORMS ASSOCIATED WITH COLD SURGES RESULTED IN 231.1 MM OF RAINFALL IN APRIL, MAKING IT THE FIRST MONTH SINCE SEPTEMBER 1973 WITH ABOVE AVERAGE RAINFALL. HOWEVER, THE HEAVY RAINS WERE CONFINED TO THREE DAYS, AND THE MONTH WAS SUNNIER THAN USUAL. THE STRONG MONSOON SIGNAL WAS HOISTED ON APRIL 1 - 2 WHEN A STRONG NORTHERLY SURGE AFFECTED HONG KONG. TROPICAL STORM BABE FORMED NEAR THE CAROLINE ISLANDS ON APRIL 26. IT MOVED NORTHWARDS AND BECAME EXTRATROPICAL SIX DAYS LATER.
DRY CONDITIONS RETURNED IN MAY AND THE RAINFALL FOR THE. MONTH WAS MORE THAN 30 PER CENT BELOW AVERAGE. MORE THAN HALF OF THE MONTH'S RAIN FELL ON MAY 2 WHEN AN ACTIVE TROUGH OF LOW PRESSURE PASSED THROUGH HONG KONG FROM THE NORTH. A SECOND TROUGH ARRIVED ON MAY 30 AND HEAVY THUNDERSTORMS ASSOCIATED WITH IT RESULTED IN THE DEATH OF THREE CAMPERS ON LANTAU ISLAND.
ALTHOUGH THERE WERE ONLY FIVE DAYS IN JUNE WITH NO RAINFALL RECORDED AT THE ROYAL OBSERVATORY, THE TOTAL RAINFALL FOR THE MONTH WAS STILL 20 PER CENT BELOW AVERAGE. THE MONTH WAS CLOUDY AND A LATE SURGE OF THE WINTER MONSOON ON JUNE
5 - 6 NECESSITATED THE HOISTING OF THE STRONG MONSOON SIGNAL FOR 21 HOURS.
FOUR TROPICAL CYCLONES WERE OBSERVED DURING THE MONTH AND TWO AFFECTED HONG KONG. A TROPICAL DEPRESSION WHICH FORMED OVER THE SOUTH CHINA SEA ON JUNE 6 CAUSED PERIODS OF STRONG WINDS AT HONG KONG ON JUNE 6 7 WHILE TYPHOON 'DINAH', WHICH DEVELOPED OVER THE PACIFIC ABOUT 50 MILES OF YAP, BROUGHT STRONG TO GALE FORCE EASTERLIES ON JUNE 12. HOWEVER, BOTH TROPICAL CYCLONE WERE RELATIVELY DRY AND WERE ASSOCIATED WITH VERY LITTLE RAIN AT HONG KONG.
JULY WAS WARM AND SUNNY WITH BELOW AVERAGE RAINFALL AND THE MEAN RELATIVE HUMIDITY OF 78 PER CENT WAS THE THIRD LOWEST ON RECORD FOR THE MONTH. FOUR TROPICAL CYCLONES FORMED IN THE WESTERN NORTH PACIFIC DURING THE MONTH BUT ONLY ONE, 'TYPHOON IVY', BROUGHT GALES TO HONG KONG.
AUGUST WAS EVEN LESS HUMID THAN JULY AND THE MEAN RELATIVE HUMIDITY OF 76 PER CENT WAS THE LOWEST EVER RECORDED FOR THE MONTH. IT WAS ALSO MUCH WARMER THAN USUAL AND THE MEAN MAXIMUM TEMPERATURE OF THE MONTH, 32.0 DEGREES CELSIUS, WAS THE THIRD HIGHEST ON RECORD. ON AUGUST 20, UNDER THE INFLUENCE OF THE SOUTHWEST MONSOON THE AIR TEMPERATURE ROSE TO 34.3 DEGREES CELSIUS WHICH WAS THE MAXIMUM RECORDED IN THE YEAR. SLIGHTLY COOLER CONDITIONS WERE EXPERIENCED AFTER THE ARRIVAL OF AN EARLY SURGE OF THE WINTER MONSOON ON AUGUST 25 AND FIRE DANGER WARNINGS WERE IN FORCE ON AUGUST 25 - 27.
ALTHOUGH SEVEN TROPICAL CYCLONES WERE REPORTED DURING THE MONTH, NONE CAME SUFFICIENTLY CLOSE TO AFFECT HONG KONG. THIS WAS THE FIRST OCCASION SINCE 1969 WHEN NO SIGNALS WERE HOISTED IN THE MONTH OF AUGUST.
/DRY AND