August 2018 was indeed unusual, as most of the nation was colder than normal and also colder than July.
Sydney itself has had a most unusual winter with the mean maximum temperature for August 0.7 degrees lower than July. The last time this occurred was in 1975. In 2014, August was also colder than July, but over 210mm of rain fell in Sydney.
The monthly rainfall pattern this year has continued to run parallel to 1975 in Sydney, but the heavy rain which fell in the Albury-Wodonga region from August 1975 to December 1975 has not eventuated this year to date.
July and August in Sydney this year were the driest since 1995 with similar dry periods in 1871, 1907 and 1927. These four years were not as wet as the last five months of 1975 in the region.
In Western Australia, Broome has had its coldest August since 1901 with the mean temperature for August of 20.3 the lowest since 19.8 in August 1901, the time the so-called long Federation Drought began and continued in our region for 18 months.
Marble Bar had its coldest August since 1968 and other colder Augusts were in 1901, 1933 and 1953. These four years saw the heaviest rains in October but very hot weather in mid-November and again just before Christmas in our region.
The active low pressure trough, although extending well into the Tropics on August 31, brought isolated thunderstorms to our regions but again very light rainfalls.
The low pressure trough had a warm front in its system this time. In Melbourne once the rain stopped and the north wind picked up during the night, the temperature rose to 17 degrees before dawn on Friday, August 31.
Adelaide also felt the effects of this warm front, recording its warmest-ever August night of 19.4. The previous warmest August night in Adelaide was 18.4 on August 30, 1993, with the next warmest 17.4 in 2005.
Coonabarabran has had two worst dry winters in succession, similar to 1926 and 1927. There was above-average rain from October 1927 right through to March 1928. Surely the big dry should finally break next October after a warm, dry September. When one looks at the rainfall figures, 1871, 1927 1933, 1975, 1993 and 2005, were all very wet. The first 40 degrees for the coming season was recorded at Fitzroy Crossing, WA on September 4, the third-earliest date. The earliest date was recorded at Kalumburu on August 27, 1970.
Heavy rain fell at Byron Bay, Ballina and Yamba, matching previous occurrences for this time in 1954, 1982 and 2006. All led to a warm, dry September. The early 40 degrees in WA could result in warm, dry conditions early in October before heavy rain later in the month.