Australian Monthly Climate Summary: May 2007
Monday 4th June, 2007
May 2007 was an exceptionally warm month in Australia, particularly in the eastern half of the country where it was the warmest May on record over large areas. Both daytime maximum and overnight minimum temperatures were well above normal over most of eastern and northern Australia. Only the southern half of Western Australia was relatively cool, with temperatures slightly below normal.
Monthly mean temperatures averaged over Australia were the second-highest on record (anomaly +1.70°C), behind the 2.03°C set in May 1958. It was the warmest May on record over all four eastern states, Queensland (+2.53°C), New South Wales (+2.08°C), Victoria (+2.34°C) and Tasmania (+2.48°C), with Tasmania experiencing its largest monthly mean temperature anomaly for any month, breaking the record of +2.35°C set recently, in February 2007. Mean monthly temperatures were at record levels over most of the eastern states (except for Cape York Peninsula and parts of northern New South Wales), as well as over eastern South Australia.
Neither daytime maxima nor overnight minima were quite as relatively extreme as the combined mean, but both still set records over substantial areas. Maxima over Australia were 1.81°C above normal (equal 3rd highest on record), with records set over all four eastern states, although by generally smaller margins than for the means. Conditions were particularly extreme in Queensland, where records were set in most areas except the far north, and in Tasmania, where they were set almost statewide. Records were also set in southern Victoria and north-eastern New South Wales. Anomalies exceeded +2°C over most of this area, and were +3 to +4°C over most of inland Queensland, and around Alice Springs. A heatwave in the tropics early in the month saw new state records for May set in Queensland (39.3°C at Julia Creek) and the Northern Territory (38.6°C at Timber Creek and Daly Waters). The only areas with below-average maxima for May were the south-west of Western Australia and around Cooktown in Queensland.
Minimum temperatures over Australia were 1.59°C above normal (3rd highest on record), with state records set in Victoria and Tasmania. They were below average only in the southern half of Western Australia (locally −2°C around Warburton) and on the mid-north coast of New South Wales. Anomalies exceeded +2°C over most of Victoria and Tasmania, much of inland New South Wales and Queensland, the Northern Territory outside Arnhem Land, and the Kimberley, and reached +3°C over parts of western Queensland and the eastern Northern Territory, as well as around Albury. Record values occurred in most of Tasmania, parts of western Queensland, south-western and north-eastern Victoria, and south-eastern South Australia. The lack of autumn frosts was particularly notable, with Canberra failing to record a night below 0°C by 1 June for the first time ever.
* Anomaly is the difference from the long-term average
Rainfall was below normal in much of Queensland and Western Australia but near- to above-normal through most of the rest of the country. Australia as a whole was 26% below normal (48th driest of 108 years), with Western Australia 56% below normal and Queensland 48% below the long-term average. This marks another dry start to the growing season in south-western Australia after the extremely dry conditions of 2006, with some areas in the lowest decile, whilst the most severely drought-affected areas in south-east Queensland remained very dry.
In contrast, Tasmania (56% above normal, 9th highest on record) had its wettest month since August 2005, and it was also rather wet through northern and western Victoria and much of western New South Wales, potentially indicating the early stages of a recovery from the severe 2006 drought. The north-west of New South Wales was particularly wet with record highs locally in the far north-west around Tibooburra. It was also wetter than normal through large parts of the northern tropics, although in general this reflected light falls in seasonally dry areas, with only a few areas exceeding 50 mm.