Australian Seasonal Climate Summary: Spring 2008
Monday 1 December, 2008
Spring was wetter than normal across much of Australia, with a very wet November offsetting drier months in September and October. It was also a rather warm season, despite low daytime temperatures under cloud cover in many areas in November.
Both daytime maximum and overnight minimum temperatures for the season were well above normal with seasonal anomalies for Australia of +0.85°C (11th highest since 1950) and +1.01°C (4th highest) respectively. Overnight minimum temperatures were particularly high in the Northern Territory and Queensland where they were the second and third-highest on record respectively (in both cases ranking behind spring 2005). The strongest maximum temperature anomalies were in Victoria, where daytime temperatures were the fourth-highest on record (anomaly +1.57°C), although 2006 and 2007 (which rank first and second) were even warmer.
Daytime maximum temperatures were above normal throughout the continent except in the southern half of Western Australia (where they were locally 1°C below normal north-east of Perth and around Esperance). Large parts of the continent were at least 1°C above normal, with the largest anomalies (around +2°C) found in north-eastern Victoria, and in southern New South Wales from Canberra westwards to the Riverina. Maxima in the highest decile covered large parts of the northern tropics, with much of the NT Top End having its hottest spring on record, and the Kimberley and north-western Queensland also ranking in the top 10%. A second large area of maxima in the highest decile covered most of Victoria, southern inland New South Wales and southern South Australia.
Above-normal minimum temperatures were even more widespread, with the only areas cooler than normal being much of northern and eastern Victoria, the Gascoyne and south Pilbara regions in Western Australia, and the Hunter Valley in New South Wales. Nights averaged at least 1°C above normal in large areas, including most of Queensland (except for the coast between Townsville and Bundaberg), northern South Australia and adjacent south-eastern areas of Western Australia, the southern and eastern Northern Territory, the western Kimberley, and a strip extending from north-western New South Wales south-east to Canberra. Most of this region was in the highest decile, and records were set around Broome where anomalies reached near +2°C.
* Anomaly is the difference from the long-term average
Rainfall averaged over Australia for the season was 21% above the long-term average (26th highest of 109 years). Western Australia (54% above normal) was particularly wet, having its ninth-wettest spring on record (with the southwest region ranking eleventh). In contrast, the south-eastern states were dry over the season despite making up some ground in November, with Victoria (36% below normal) having its 15th driest spring on record, and South Australia and Tasmania both marginally below the long-term average.
Rainfall was above normal almost throughout Western Australia, except for the far north and a small area around Geraldton. It was also wetter than normal in much of the Northern Territory away from the Top End, large parts of Queensland, the far north of South Australia, the northern half of New South Wales and parts of East Gippsland in Victoria.
The most substantial very wet areas, with rainfalls in the highest decile, were much of southern Western Australia (south of the Indian-Pacific railway) away from the west coast, much of the Pilbara and northern WA Goldfields, and around Alice Springs, with records being set locally in a strip between Hyden and Esperance, and south of Alice Springs. There were also scattered patches in the highest decile through much of Queensland (including the Brisbane area) and in north-eastern New South Wales.
In contrast, it was a very dry season in substantial parts of southern South Australia and western Victoria, where November rainfall was near or below normal and was insufficient to make up the large deficits accumulated during the first two months of the season. Spring rainfall was in the lowest decile in most of the agricultural areas of South Australia, south of a Ceduna-Port Augusta-Renmark line (including the Eyre Peninsula), as well as in the west and south of Victoria south of a Melbourne-Horsham-Renmark line, and in west Gippsland from Wilsons Promontory westwards. Spring rainfall was 50% or more below normal in most of this area, although few records were set as spring 2006 was generally even drier there.