Australia in June 2017

In brief

A very dry month

Nationally, the second-driest June on record, with rainfall 62% below average for Australia as a whole

June has been the driest on record for large areas of southern Australia

Persistent high pressure and a lack of cold fronts crossing southern Australia were largely responsible for the absence of rainfall

Daytime temperatures above average across most of the country, especially in southwestern Australia

Overnight minimum temperatures below average across much of southern mainland Australia, but above average for the central east coast, associated with areas of higher cloud cover and rainfall

Temperatures

Daytime temperatures during June were above to very much above average over the majority of the country. The mean maximum temperature for Australia as a whole was the seventh-warmest on record for June, at 1.33 °C above average. For Western Australia it was the third-warmest June on record, and for Queensland the ninth-warmest.

The national mean minimum temperature was 0.40 °C cooler than average. Despite much cooler than average nights across a large part of the southern mainland, only South Australia placed within the ten coolest Junes, with mean minimum for the month the seventh-coolest on record.

Maximum temperatures for June were in the highest 10% of historical observations (decile 10) for southern Queensland; inland northeastern New South Wales, extending southward into the Central Tablelands; for eastern to central Tasmania; areas of South Australia between the North East district, the Eyre Peninsula, and the greater Adelaide region; and across the south and west of Western Australia. Days were the warmest on record for June across the South West Land Division in Western Australia, extending just into the Eucla and Goldfields districts. Many long-term stations in Western Australia had their warmest June days on record.

Minimum temperatures were below average for most New South Wales away from the northeast, most of Victoria, most of South Australia away from the north, and for southeast Western Australia. Mean minima were in the lowest 10% of historical observations (decile 1) for much of this area as persistent high pressure systems brought long strings of clear, cold nights, with records set in some parts of southern inland New South Wales and northern Victoria. Nights were also cooler than average over a broad area from the southern Kimberley to the southwestern Northern Territory, and smaller areas of the southern Top End, on the centre of the border between the Northern Territory and Queensland, and in eastern Queensland on and inland of the Central Coast.

Minimum temperatures were above average across central coast to northeastern New South Wales and far southeastern Queensland, western Tasmania, and areas of Western Australia in the coastal Pilbara, central Gascoyne, northern Kimberley coast, and central southern coast. Nights were also warmer than average for areas of the tropical northern coasts around the Top End, Gulf of Carpentaria, and Cape York Peninsula.

Areal average temperatures Maximum Temperature Minimum Temperature Mean Temperature Rank

(of 108) Anomaly

(°C) Comment Rank

(of 108) Anomaly

(°C) Comment Rank

(of 108) Anomaly

(°C) Comment Australia 102 +1.33 = 40 −0.40 80 +0.47 Queensland 100 +1.50 75 +0.71 89 +1.11 New South Wales 98 +1.31 31 −0.62 73 +0.34 Victoria = 78 +0.51 12 −1.27 35 −0.37 Tasmania 91 +0.59 71 +0.35 80 +0.47 South Australia 94 +1.13 7 −1.77 42 −0.31 Western Australia 106 +1.72 53 −0.26 87 +0.73 Northern Territory 80 +0.71 33 −0.86 56 −0.07

Rank ranges from 1 (lowest) to 108 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.

Temperature maps Mean Anomaly Deciles Mean

daily

maximum

temperatures Mean

daily

minimum

temperatures Mean

daily

temperatures

Rainfall

Rainfall during June was below average for most of Australia, and lowest on record for much of inland northern and northeastern Victoria, adjacent inland southern New South Wales, parts of southwest and western Western Australia, and eastern Tasmania. The national area-average June rainfall was 62% below the long-term mean, coming in as the second-driest June on record. Across the country, more than 100 stations with more than 50 years of observations have reported their lowest June rainfall total on record, and for Victoria as a whole it was the driest June on record.

June saw seasonally dry conditions for most of the north of Western Australia, the Northern Territory, and most of Queensland away from the east coast and inland southeast. Below average rainfall was also reported in areas of Queensland extending from around Townsville, to the Central West district, and to the central south.

The only areas with significantly above average rainfall were on the east coast between Sydney and Brisbane. Out-of-season rainfall also brought above average totals to parts of pastoral South Australia and the interior of Western Australia.

This very dry June was largely due to higher than average mean sea level pressure (MSLP) patterns across southern Australia, associated with a positive phase of the Southern Annular Mode (SAM). With the subtropical ridge both stronger, and further south, than usual for this time of year, persistent areas of high pressure reduced the number of rain-bearing low pressure systems and cold fronts affecting southern Australia and reduced cloudiness over land. MSLP has been more than 5 hPa above average for June across much of southern Australia; many sites with long-term MSLP data observed record high mean 9 am MSLP for June, including all but one of the sites in South Australia, and all but three in Victoria.

The latest Climate Outlook suggests the southward shift of the sub-tropical ridge is likely to continue, with SAM forecast to be positive at least for much of July. Mean sea level pressure over southern Australia has been increasing in winter over recent decades. This pattern is consistent with future climate change projections for the Australian region.

Area-average rainfall Rank

(of 118) Average

(mm) Departure

from mean Comment Australia 2 8.8 −62% Queensland 16 5.0 −73% New South Wales 26 25.5 −34% Victoria 1 13.7 −77% Tasmania 7 64.2 −50% South Australia 29 9.9 −48% Western Australia 9 7.9 −69% Northern Territory 33 0.9 −87% Murray-Darling Basin = 4 11.0 −67%

Rank ranges from 1 (lowest) to 118 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Departure from mean is relative to the long-term (1961–1990) average.

Rainfall maps Totals Percentages Deciles Total

rainfall

Australian weather extremes during June 2017 Hottest day 34.7 °C at Fitzroy Crossing Aero (WA) on the 25th Coldest day −2.4 °C at Thredbo AWS (NSW) on the 6th Coldest night −9.6 °C at Perisher Valley AWS (NSW) and Liawenee (Tas.) on the 27th Warmest night 26.6 °C at Coconut Island (Qld) on the 2nd Wettest day 133.6 mm at Evans Head RAAF Bombing Range AWS (NSW) on the 10th