South East Queensland: Climate and water

  • Total annual rainfall for the 2021–22 year was the region's second wettest year on record, behind 1974–75.
  • February 2022 was the wettest February on record and second wettest month (for any month) on record for the region.
  • Near-record rainfall resulted in some streamflows being almost five times above the annual average.

Schematic representation of the South East Queensland region. In 2021–22, rainfall was 1,024 mm, less than average for the sixth consecutive year. Streamflow in Brisbane River in 2021–22 was 11 GL compared to the average value of 237 GL. Soil moisture was average.

For further information on the region's climate and water conditions during the 2021-22 year scroll down this page or click on the links below:

 

About the region

  • The South East Queensland region has a subtropical climate. Rainfall occurs throughout the year with most rainfall occurring during the summer and autumn months. Higher streamflows typically occur during these months.

 

Climate conditions

Rainfall

Figure C1 Annual and monthly rainfall deciles for the South East Queensland region during the 2021-22 year

  • Total area-averaged rainfall for the 2021-22 year was 1,936 mm; 183% above the mean value of 1,056 mm.
  • A weak negative Indian Ocean Dipole (IOD) and developing La Nina influenced rainfall over South East Queensland, particularly during spring and summer.
  • The annual rainfall in 2021-22 was the second highest on record, behind only 1974-75. It was also the sixth wettest 24-month period on record, and the wettest 24-month period since 2011-13.
  • Rainfall was average to below-average across most of the region during August and September; a result of the IOD temporarily weakening during those months. However, the resurgence of the IOD in October and the development of La Nina in November resulted in rainfall being more than twice the long-term average for both October and November.
  • The 2021-22 La Nina event peaked by late January, resulting in the wettest February since records began in 1900, and the second wettest month overall for South East Queensland. It was also the wettest October to March period on record.
  • Despite a weakening La Nina losing its influence on rainfall over the region throughout autumn, rainfall during March and April was predominantly average to above average.
  • A deep low-pressure trough caused near-record rainfall over the region during May, with some areas recording their highest May daily and monthly rainfall totals on record. Overall, it was the region's second wettest May on record.
  • Although La Nina-like conditions lingered in the atmosphere, rainfall during June was predominantly below average across the region.

 

Figure C2 Total monthly rainfall for the South East Queensland region during the 2021-22 year compared with the average and percentiles for the region

  • Rainfall was above the 90th percentile for October 2021, November 2021, February 2022, and May 2022, contributing to the second wettest year on record.
  • February 2022 was the wettest February on record, and the second wettest month on record (for all months). It was also the region's second wettest May on record.
  • No month recorded rainfall below the 10th percentile, however, August 2021, September 2021, and June 2022 were all well below their respective monthly averages.

 

Actual evapotranspiration

Figure C3 Annual and monthly actual evapotranspiration deciles for the South East Queensland region during the 2021-22 year

  • Total area-averaged actual evapotranspiration for the 2021-22 year was predominantly very much above average, including some areas experiencing their highest evapotranspiration on record.
  • Evapotranspiration was predominantly above average during July; a result of above-average rainfall. However, after below-average rainfall throughout August and September, evapotranspiration had reversed by September, with roughly half the region registering below-average evapotranspiration.
  • From October onwards, evapotranspiration was predominantly above average, with areas having record evapotranspiration across several months; a reflection of the wettest October to March period on record.
  • By June 2022, evapotranspiration remained above average across most of the region.

 

Soil moisture

Figure C4 Annual and monthly soil moisture deciles for the South East Queensland region during the 2021-22 year

  • Soil moisture in the root zone (0–1 m depth) was above average during the 2021-22 year, with some areas experiencing their highest soil moisture on record.
  • During the first three months (July to September 2021), soil moisture was predominantly average, but gradually dried by September.
  • Above-average rainfall during October and November lead to an increase in soil moisture across the region. By December, soil moisture was at least above average across the entire region, and remained predominantly above average during January.
  • Despite record rainfall in the six months from October to March, soil moisture remained predominantly average to above average across this period, with soil moisture being very much above average in some areas.
  • The second wettest May on record resulted in soil moisture being above average across the entire region during May and predominantly above average in June.
  • More information on soil moisture distribution across the region is available in the Australian Water Outlook.

 

Streamflow responses

Map of key gauging stations. North Maroochy River at Eumundi, station number 141009A, is located in the north of the region. Brisbane River at Gregors Creek, station number 143009A, is in the northwest of the region. Bremer River at Walloon, station number 143107A, is near the town of Ipswich. Logan River at Yarrahappini, station number, 145014A, and Albert River at Bromfleet, station number 145102B, are in the southern part of the region.
Figure C5 Key flow gauging stations along the main rivers within the South East Queensland region

  • The five main rivers in the region are the Albert, Brisbane, Logan, Bremer and Maroochy rivers.
  • The seasonal flow characteristics of these rivers reflect the rainfall pattern of the region, where most rainfall occurs between November and March.

 

Figure C6 Total monthly flow for major rivers in the South East Queensland region during the 2021-22 year compared with the average and percentiles

  • Streamflows were average to below average for the first four months of the 2021-22 year. However, following above average rainfall during October and November, streamflows increased above the long-term average flow volumes at most sites. By December, streamflows were above the 90th percentile at all sites, except for the North Maroochy River at Eumundi (Station 141009A).
  • Following record-breaking rainfall during February, streamflows peaked at record or near-record flow volumes at all sites during February, and remained well above the 90th percentile into March.
  • Drier conditions in April resulted in streamflows falling below the 90th percentile, except for the Logan River at Yarrahappini (Station 145014A).
  • Streamflows during May rose well above the 90th percentile following the second wettest May on record. All streamflows returned to average flow volumes in June; a result of below-average rainfall during June.