The 2009 southeastern Australia heat wave was a heat wave that lasted from 25 January to 8 February and led to record-breaking prolonged high temperatures in the region. The heat wave is considered one of the, if not the, most extreme in the region's history. During the heat wave, fifty separate locations set various records for consecutive, highest daytime and overnight temperatures. The highest temperature recorded during the heat wave was in Hopetoun, Victoria, a record for the state that stood until 2026. Many locations through the region recorded all-time high temperatures including capital cities Adelaide, which reached its third-highest temperature, , and Melbourne, which recorded its highest-ever temperature on record, . Both cities broke records for the most consecutive days over , while Mildura, Victoria recorded an all-time record twelve consecutive days over .
The exceptional heat wave was caused by a slow-moving high-pressure system that settled over the Tasman Sea, with a combination of an intense tropical low located off the North West Australian coast and a monsoon trough over Northern Australia, which produced ideal conditions for hot tropical air to be directed down over southeastern Australia. The heat began in South Australia on 25 January but became more widespread over southeast Australia by 27 January. A weak cool change moved over the southern coastal areas bringing some relief on 30 January, including Melbourne, where the change arrived that evening, dropping temperatures to an average of . Higher temperatures returned on the following weekend with Melbourne recording its hottest day since records began in 1855, .
The heat wave generated extreme fire conditions during the peak of the 2008–09 Australian bushfire season, causing many bushfires in the affected region, contributing to the extreme bushfire conditions on 7 February, also known as the Black Saturday bushfires, which claimed 173 lives in Victoria.
Cause The heat wave was caused by a slow-moving high-pressure system that settled over the Tasman Sea. Coupled with an intense tropical low and a monsoon trough over Northern Australia, this produced hot, tropical air to be directed over southeastern Australia, raising temperatures significantly. The CSIRO stated that "The warm lower tropospheric anticyclone is the key synoptic weather system responsible for the heat-waves." The heat wave was the worst in Australia's history.
Records and statistics During the heat wave, several records were broken; Tasmania recorded its highest-ever temperature; in Scamander, and the long-standing Tasmanian record of (recorded in Hobart on 4 January 1976) was broken five times within two days at Flinders Island, Fingal (twice), St Helens and Scamander, while Hopetoun in Victoria recorded the highest temperature of the heat wave, , which was a state record until 2026.
Adelaide, South Australia Average daily maximum 27 January – 7 February: – (11.1 °C (20.0 °F) above average) 13 Consecutive days over 6 Consecutive days over 4 Consecutive days over
Melbourne, Victoria Average daily maximum 27 January – 7 February: – (10.1 °C (18.2 F) above average) 12 Consecutive days over 5 Consecutive days over 3 Consecutive days over
Mildura, Victoria 12 Consecutive days over 5 Consecutive days over
Wagga Wagga, New South Wales 14 Consecutive days over 13 Consecutive days over 4 Consecutive days over
Temperatures (daily maximum)
Avalon, Victoria January 2009 27th – 28th – 29th – 30th – February 7th – (record high, 2.1 °C higher than previous record)
Ceduna, South Australia January 2009 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th –
Mildura, Victoria
January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th – – 12th consecutive day over 40 °C 8th –
Deniliquin, New South Wales January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th –
Swan Hill, Victoria January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th –
Melbourne, Victoria
Temperatures have been recorded since 1855.
January 2009 27th – 28th – 29th – 30th – – Third-hottest day recorded in Melbourne. 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th – – Hottest day recorded in Melbourne 0.8 °C hotter than previous record (Friday, 13 January 1939).
Adelaide, South Australia January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th –
A record-high minimum temperature was recorded at around midnight on 29 January, when the temperature dropped to only at the Bureau of Meteorology weather station in Kent Town, near the Adelaide city centre. Temperatures recorded in other parts of the city and other towns throughout South Australia were even higher.
Woomera, South Australia January 2009 25th – 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th –
Wagga Wagga, New South Wales
January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th – – Hottest day recorded in Wagga Wagga since records began in 1941. 8th –
On 31 January 2009, Wagga Wagga broke the all-time January record for the most days above with six days recorded (the record previously being five days, which was set in 1952 and equalled in 1979 and 2001). The January record set in 1979 was equalled for number of days above or more which is 19 days.
Wagga Wagga broke the all-time record and the February record for the highest recorded maximum on 7 February 2009, 2:50pm AEDT the city recorded with the previous February record being set on 1 February 1968 and the all time previously being set on 23 January 2001.
On 8 February 2009, the record for consecutive days over was broken with thirteen consecutive days recorded (the previous record being six days, which was set in 1946 and equalled in 1979, 1980 and 2004). Wagga Wagga also recorded fourteen consecutive days of over .
Albury–Wodonga, NSW/VIC January 2009 26th – 27th – 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th – – Hottest day recorded in Albury–Wodonga since records began in 1973. 8th –
Ballarat, Victoria January 2009 28th – 29th – 30th – February 7th – (record-high, 2.1 °C higher than previous record)
Canberra, ACT January 2009 28th – 29th – 30th – 31st – February 1st – 2nd – 3rd – 4th – 5th – 6th – 7th – 8th –
Launceston, Tasmania January 2009 28th – 29th – 30th – – Hottest day recorded in Launceston since records began in 1980. 31st –
Accompanying bushfires
After a slow start to the 2008–09 Australian bushfire season, the high temperatures and wind precipitated several bushfires across Victoria and South Australia. The conditions were very similar to the heat wave experienced in early January 1939, which killed 438 people and precipitated the Black Friday bushfires of 1939.
Fires were also started in the Australian Alps by lightning strikes from dry thunderstorms in north-east Victoria and south-east New South Wales.
The tail end of the heat wave also precipitated the Black Saturday bushfires, in which 173 people died, 414 injured and 2,029 houses destroyed at various locations across the state. Several locations around the state recorded their highest temperatures since records began in 1859 and winds gusted up to 110 km/h.
Comparison to normal climate for the area Many areas in central South Australia, northern Victoria and inland New South Wales regularly experience temperatures over for one, two or three consecutive days, sometimes more, during the summer months. During the heat wave, however, many of these regions experienced temperatures over for twice as long or more, on average, than is normal for that time of year. Coastal regions and the ACT experienced slightly lower temperatures; however, these were still above average and lasted for a prolonged period.
While coastal regions may have experienced shorter periods of heat wave, for the time that they did experience temperatures over , they mostly reached the top 3, top 5 or top 10 all-time temperature records for a number of days.
The heat wave was perhaps most extreme in northern and eastern Tasmania, where 7 of the 8 highest temperatures recorded in Tasmania up to that time occurred during the heat wave.
A chart of the variation of maximum and minimum daily temperatures, through the year, for Melbourne was prepared from observations between May 1855 and August 2006. For early February, this shows a mean daily maximum temperature of with the 75th-percentile temperature being about .
Effects
Energy Localised power outages occurred throughout both cities during the week at varying times for various lengths. It is estimated that over 500,000 residents in Melbourne were without power for the evening of 30 January 2009. The outage affected much of central Melbourne with train and tram services cancelled, the evacuation of Crown Casino, traffic light failures, people being rescued from lifts and patrons of the Victorian Arts Centre evacuated and shows cancelled. The outage occurred only an hour after the National Electricity Market Management Company (NEMMCO) issued a statement saying load shedding was ending and power had been restored.
Blackouts also occurred in the city's west, caused by the three-day heat wave. It is believed an explosion at South Morang contributed to the power problems along three transmission lines supplying Victoria's west and Victorian power supplier SP AusNet shed 1,000 megawatts. On the 30th, Energy Minister Peter Batchelor announced consumers who lose power for more than 20 hours would be eligible for compensation.
Areas that did not experience blackouts still had problems with abnormally low voltage (probably due to increased air-conditioner usage).
As of 1 February, the heat wave is estimated to have cost the Victorian economy $100m during the week.
Transport Over the course of the week, thousands of train and tram services were cancelled in both cities, with more than 1,300 individual train services cancelled in metropolitan Melbourne alone. The cancellations were due to buckling rail lines, air conditioner failures and power outages. On the 30th, all public transport in the city was free as the government admitted responsibility for failing to provide adequate infrastructure elements to cope with the heat, as well as long-standing issues with underfunding. On the 30th, 730 (40%) of rail services were cancelled, the worst day of operation since Connex took control in 2004.
2009 Australian Open Several outdoor matches during the 2009 Australian Open on the 29th and the 30th were cancelled due to the heat. A number of players, including number 3 seed Novak Djokovic, cited the temperature as reason for withdrawing from matches. Serena Williams was quoted as saying it was so hot on court she felt like she was having an "out-of-body experience". After these retirements and an intensification in the heat, the organisers responded by closing the roof and allowing players longer breaks and icepacks.
Human health There is dispute between sources as to how many people were affected by the heat wave. Hundreds were treated for heat-related illness and 6 fatalities were confirmed, and a number of "sudden deaths" were suspected to be caused by the heat. Authorities worked through each case to determine exactly how many fatalities were directly attributable to the heat wave.