Australia in May 2023

In brief

• Australia's second-driest May on record, aided by a persistent positive anomaly of mean sea level pressure that resulted in cloud-free conditions over most of the country.
• Averaged across Australia as a whole, rainfall was 72.8% below the 1961-1990 average for May.
• May rainfall was below average across most of Australia except for small areas in the east and south-east.
• Australia's national mean temperature was 1.10 °C below the 1961-1990 average for May, the lowest since 2011.
• Australia's mean maximum temperature for May was 0.12 °C below average and the mean minimum temperature was 2.11 °C below average, the seventh-lowest on record and the lowest since 1944.
• Mean maximum temperatures were cooler than average for large parts of northern and south-eastern Australia. Mean maximum temperatures were warmer than average for parts of north-eastern Queensland and most of Western Australia's Gascoyne and South West Land Division.
• Mean minimum temperatures were cooler than average for most of the eastern two thirds of the country and warmer than average for northern parts of Cape York Peninsula.

Further information and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, published on 5 June 2023.

Temperatures

Australia's national mean temperature was 1.10 °C below the 1961-1990 average for May, the lowest since 2011. The national mean maximum temperature for May was 0.12 °C below average and the mean minimum temperature was 2.11 °C below average, the seventh-lowest on record and the lowest since 1944.

Mean maximum temperatures were cooler or much cooler than average for much of Kimberley and Northern Interior of Western Australia, most of the Northern Territory extending into western Queensland, large parts of South Australia, inland eastern New South Wales and most of Victoria away from the north-west.

For the Northern Territory as a whole, the mean maximum temperature was close to 1.5 °C below average. Large areas of the Northern Territory and western Queensland had mean maximum temperatures in the lowest 10% of historical observations for May (compared with all Mays since observations began in 1910).

On 7 May and again between 28 and 30 May, large parts of Australia experienced daily maximum temperatures more than 4 degrees cooler than average for May. Some stations had their lowest daily maximum temperature for May on record on these days.

Mean maximum temperatures were warmer or very much warmer than average for parts of north-eastern Queensland and most of Western Australia's Gascoyne and South West Land Division.

Mean minimum temperatures were cooler or much cooler than average for much of Australia. Mean minima were in the lowest 10% of historical observations for May for large parts of northern Western Australia, the Northern Territory, Queensland, New South Wales and north-eastern South Australia. Many sites had their lowest May mean daily minimum temperature on record or the lowest for at least 20 years.

Clear skies and light winds under the ridge of a high pressure system combined with cold south-westerly airflow that followed the passage of cold fronts resulting in low daily minimum temperatures in large parts of the country between 7 and 11 May, and again between 27 and 31 May. Many sites had their lowest May temperature on record and frost was observed in large inland areas of eastern and south-eastern Australia.

Mean minimum temperatures were warmer or much warmer than average for northern parts of the Cape York Peninsula.

Rank ranges from 1 (lowest) to 114 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.

Rainfall

May was an exceptionally dry month for Australia; nationally, it was the second-driest May on record (since observations began in 1900). The month was marked by succession of high pressure systems which brought settled weather conditions for most of the country and kept cold fronts southwards.

For Australia as a whole, rainfall was 72.8% below average for May.

May rainfall was below average for most of Australia, and in the lowest 10% of historical observations for May (compared with all Mays since observations began in 1900) for large parts of Western Australia, western South Australia and adjacent parts of the Northern Territory, New South Wales and pockets of eastern Queensland.

For Western Australia, it was the driest May on record since observations begun, with statewide rainfall 88.1% below average. For the Northern Territory as a whole, May rainfall was 91.8% below average, while for Queensland and New South Wales state-wide May rainfall was more than 70% below average.

Only small areas of Australia received above average rainfall for the month - inland south-eastern Queensland (due to showers that developed mid-month in the on-shore airflow) and parts of eastern Victoria and western Tasmania (due to cold fronts and associated rainfall).

Significant weather and records

Wintery weather in south-eastern Australia

A cold front swept across southern South Australia, Tasmania, Victoria and southern New South Wales on 3 May, bringing showers and strong, gusty winds to Victoria and New South Wales and snow to Alpine areas.    

Another cold front, associated with a deep low pressure system centred well south of Australia, crossed the south-east of the country between the 5th and 7th with gusty winds, isolated thunderstorms, polar air and "speckled" cloud in a strong southerly airstream behind it. The front moved into the Tasman Sea on the 7th and developed into an off-shore low pressure system, which maintained strong, gusty and cold south-westerly winds across much of south-eastern Australia and southern Queensland.

On the 7th, large parts of Victoria, New South Wales and adjacent areas of eastern South Australia and south-western Queensland experienced daily maximum temperatures more than 4 degrees cooler than average for May. Parts of south-eastern new South Wales and north-eastern Victoria recorded daily maximum temperatures more than 8 degrees below average and some stations had their lowest May daily maximum temperatures on record on this day. Cooma Airport, where observations began in 1990, had maximum temperature of 2.7 °C, a May record by 2.2 °C, and the fifth-lowest daily maximum temperature for this site in any month.

Many locations in south-east New South Wales and north-east Victoria reported snow fall down to 700 m on the 7th and 8th, while Alpine areas had 10 to 20 cm of snow. Parts of Australian Capital Territory and Victoria reported heavy hail on the 7th.

Clear skies and light winds under the ridge of a high pressure system combined with cold south-westerly airflow resulting in low daily minimum temperatures in large parts of eastern and central Australia between the 9th and 11th. Some sites had their lowest temperature for May on record and frost was observed in large inland areas of eastern and south-eastern Australia.

Showers on the east coast

A strong high pressure system directed onshore flow to the east Australian coast between the 12th and 16th, producing showers in coastal and some inland parts of New South Wales and Queensland. Daily rainfall totals between 30 to 50 mm, due to thunderstorms, were observed about the Gold Coast, North Tropics and Sydney basin at the beginning of the period. Thunderstorms and showers increased through south-eastern Queensland and north-eastern New South Wales on the 15th as a low pressure system started to develop off the coast. Widespread 50 to 100 mm daily rainfall totals were recorded at coastal and inland areas, locally exceeding 100 mm. The highest daily rainfall total (at a Bureau gauge) in the 24 hours to 9am on the 16th was 143.2 mm at Tweed Heads in New South Wales. Some stations had their highest daily rainfall total on record for May (although mostly at sites with less than 30 years of observations).

Damaging winds

A series of cold fronts crossed south-eastern Australia between the 15th and 21st bringing a burst of cold, wet and windy weather. With a high pressure system over southern Western Australia, a deep low pressure system south of Tasmania, and a strong change of pressure between them, a cold front that crossed Tasmania overnight between the 20th and 21st brought damaging to destructive winds with gusts in excess of 100 km/h to much of Victoria, Tasmania and southern New South Wales. Winds are generally stronger over coastal and elevated areas, and the strongest wind gusts were observed on the 21st, with 137 and 126 km/h recorded at Wilsons Promontory Lighthouse (Victoria) and Tasman Island (Tasmania) respectively. Strong winds caused disruptions to electricity supplies and widespread power outages affected various parts of Tasmania.

Another cold and gusty outbreak for south-eastern Australia

The end of autumn brought a cool and wet spell to south-eastern Australia in the last week of May. A strong cold front moved over the south-eastern states with damaging winds, thunderstorms, rain, hail, cold air and snow to low levels. The front moved out to the Tasman Sea on the 26th, generating thunderstorms and large surf for the New South Wales coast. Severe thunderstorms across the Hunter coast and Newcastle area in the afternoon of the 26th brought flash flooding, large to giant hail, waterspouts and heavy rainfall which locally exceeded 50 mm in one hour. 

Clear skies and light winds under a high pressure system, and a cold airmass, resulted in low daily minimum temperatures across large parts of south-western, eastern and northern Australia between the 27th and 31st. Some sites in southern Western Australia, New South Wales, Queensland and the Northern Territory had their lowest May temperature on record and frost was observed in large inland areas of south-eastern and eastern Australia.

Rank ranges from 1 (lowest) to 124 (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.