Monday, 3 May, 2010 — Monthly Climate Summary for Australia — Product Code IDCKGC1A00

Australia in April 2010

Temperatures Rainfall Extremes Important notes the top

In Brief

April was significantly warmer than normal over most of Australia, especially at night. Overnight minimum temperatures for Australia were the second-highest on record for April, and ranked in the top three in four states. Maximum temperatures were less extreme but were still well above normal. Rainfall was also above normal over much of the country, particularly in the interior, although it was near or below normal in many southern areas.

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Temperatures

Maximum temperatures were 0.93°C above normal (10th highest on record). The most significant warmth was in Western Australia, which was fifth-warmest on record. Daytime temperatures were at least 1°C above normal over most of the state except the north Kimberley and the western coastal strip, and were 2°C or more above normal over most inland, with anomalies reaching +4°C around Warburton. Records were set locally in the inland Pilbara. Anomalies exceeding 1°C extended into the southwestern Northern Territory and northwestern South Australia. Another area which was at least 1°C above normal was in the coastal southwest, encompassing all of Tasmania, and the eastern coastal strip between Geelong and the NSW-Queensland border.

The most significant area with below-normal maximum temperatures was a region centred on the Gulf region of northwestern Queensland and the eastern Northern Territory, with temperatures more than 1°C below normal along the Gulf of Carpentaria coast in both the NT and Queensland. Elsewhere, only a few patches had daytime temperatures slightly below normal, including areas around Mount Gambier, exposed WA coastal areas around Carnarvon and Geraldton, and some areas along the inland NSW/Queensland border.

Overnight minimum temperatures were 1.68°C above normal, the second-highest on record (ranking only behind 2005). Western Australia ranked second, and South Australia, Tasmania and Victoria all third. They were above normal almost throughout the country, the only exceptions being the far southwest of Western Australia and coastal parts of that state’s Gascoyne region. Most areas were at least 1°C above normal, except for western WA (west of a Port Hedland-Kalgoorlie-Esperance line) and the eastern half of NSW.

The strongest anomalies, more than 2°C above normal, occurred in the eastern half of Western Australia, most of the Northern Territory outside the Top End, northern South Australia, northwestern Victoria, and central and western Victoria. Anomalies exceeded +4°C around Warburton (WA), and east of Alice Springs and in the Victoria River district of the Northern Territory. Records were set in a number of regions, including much of the WA interior, the western Top End (NT), the central third of Victoria, northwestern Tasmania, parts of Cape York Peninsula, and around Ceduna (SA).

Areal average temperatures
	Maximum Temperature			Minimum Temperature
	Rank (out of 61)	Anomaly* (°C)	Comment	Rank (out of 61)	Anomaly* (°C)	Comment
Australia	52	+0.93		60	+1.68	2nd highest; record is +2.05 (2005)
Queensland	31	+0.27		57	+1.41
New South Wales	44	+0.91		48	+0.80
Victoria	53	+1.34		59	+1.73	Highest since 1974
Tasmania	56	+1.34		59	+1.35	Highest since 1989
South Australia	49	+1.11		59	+2.40	3rd highest; record is +2.65 (2005)
Western Australia	57	+1.67		60	+1.94	2nd highest; record is +2.27 (2005)
Northern Territory	30	+0.19		54	+1.58

^*Anomaly is the departure from the long-term (1961-1990) average.

Temperature maps
	Mean	Anomaly	Deciles
Mean daily maximum temperatures
Mean daily minimum temperatures

Temperatures Rainfall Extremes Important notes the top

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Rainfall

National rainfall was 34% above normal (17th highest on record). Totals were above normal across much of northern and central Australia, including almost all of the Northern Territory, Queensland west of a Townsville-Charleville line (extending into northwestern NSW west of Walgett), most of South Australia (except the Eyre Peninsula and some areas east of the Flinders Ranges), and the eastern half of Western Australia. It was also wetter than normal in April in the western half of Victoria, as well as in the northeast ranges and south Gippsland, and in northwestern Tasmania.

The two most significant areas of above-normal rainfall were in much of northeastern South Australia, and the Gulf region extending from the eastern Northern Territory as far east as southern Cape York Peninsula. April records were set in both regions, around the Queensland/NT border on the Gulf coast, further east around Croydon, and in the Woomera-Leigh Creek area in South Australia. Other areas with totals in the highest decile included the southern NT around and east of Alice Springs, and localised areas in the WA Goldfields, the NT Top End, and west of Bourke in New South Wales.

While rainfall was below normal in many southern areas, few areas were especially dry and only small areas were in the lowest decile. The greatest concentration of such areas was on the NSW coast south of Sydney; there were also patches of such low falls scattered through the inland west of Western Australia.

Areal average rainfall
	Rank (out of 111)	Average (mm)	Departure from mean*	Comment
Australia	95	41.5	+34%
Queensland	93	60.8	+45%
New South Wales	48	31.5	−34%
Victoria	67	52.0	+1%
Tasmania	56	112.8	−4%
South Australia	98	26.2	+59%
Western Australia	56	20.8	Normal
Northern Territory	101	67.8	+135%
Murray-Darling Basin	67	30.1	−23%

^*The mean is calculated for the 1961-1990 reference period.

Rainfall maps
	Totals	Percentages	Deciles
Total rainfall

Temperatures Rainfall Extremes Important notes the top

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Australian weather extremes in April 2010
Hottest day	42.8 °C at Roebourne (WA) on the 1st
Coldest day	2.1 °C at Mount Baw Baw (Vic) on the 11th
Coldest night	−8.0 °C at Charlotte Pass (NSW) on the 26th
Warmest night	30.4 °C at Marble Bar (WA) on the 1st
Wettest day	358.4 mm at Centre Island (NT) on the 1st

Temperatures Rainfall Extremes Important notes the top

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Further information

National Climate Centre
Bureau of Meteorology
Phone (03) 9669 4082
Email webclim@bom.gov.au

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