Canberra: Climate and water

  • Total annual rainfall was above average for the first time in four years.
  • Heavy rainfall in March 2021 resulted in very high streamflows during that month.
  • In late March 2021, minor to moderate flooding occurred across the region.

Schematic representation of the Canberra region. In 2020–21, rainfall was 1,128 mm, well above average for the first time in four years. Streamflow in Queanbeyan River in 2020–21 was 136 GL compared to the average value of 43 GL. Soil moisture was above average.

For further information on the region's climate and water conditions during the 2020–21 year scroll down this page or click on the links below:

 

About the region

  • The Canberra region has a relatively dry, continental climate with warm to hot summers and cool to cold winters. Rainfall in the region is relatively uniform throughout the year with a long-term monthly average of 50–75 mm.
  • Higher streamflows in the region's rivers typically occur during winter and spring following higher runoff from partially saturated catchments in autumn and winter. Streamflows in the Murrumbidgee River can also be influenced by water diversions from the Snowy Mountain Scheme.

 

Climate conditions

Rainfall

Figure C1 Annual and monthly rainfall deciles for the Canberra region during the 2020–21 year

 

  • Total area-averaged rainfall for the year was 1,128 mm, well above the mean value of 794 mm and the region's highest since 2011–12.
  • In early-August 2020, heavy rainfall associated with a coastal low contributed to well above-average rainfall across the entire region and the highest August rainfall in more than 20 years.
  • Average to above-average rainfall throughout most of the spring–summer months was due to a weak La Niña that influenced Australia's climate during this period.
  • Heavy rainfall associated with a slow-moving low pressure system that impacted the region in late-March 2021 contributed to the well above-average rainfall for that month (see the Bureau's 2020–21 Climate Report for more information).

 

 

Figure C2 Total monthly rainfall for the Canberra region during the 2020–21 year compared with the average and percentiles for the region

 

  • Rainfall in August 2020, October 2020, and March 2021 was well above the 90th percentile for those months.
  • Rainfall in April 2021 was the lowest in more than 20 years for that month.

 

Actual evapotranspiration

Figure C3 Annual and monthly actual evapotranspiration for the Canberra region during the 2020–21 year

 

  • Total area-averaged actual evapotranspiration was average to above average across the region.
  • In November 2020, evapotranspiration was well above average across almost the entire region due to increased water availability following high rainfall in October–November 2020.
  • In the following months of December 2020–January 2021, evapotranspiration was below average across most of the region due to very little rainfall occurring in the latter part of December and the first half of January.
  • Evapotranspiration was above average over the entire region during April–May 2021 due to increased water availability following the very high rainfall in late-March 2021.

 

Soil moisture

Figure C4 Annual and monthly soil moisture deciles for the Canberra region during the 2020–21 year

 

  • Soil moisture in the root zone (0–1 m depth) was well above average across the entire region.
  • Soil moisture was average in July 2020 and January 2021; and it was above average or very much above average for most of the year, reflecting the above-average rainfall experienced across the region during most months of the year.
  • More information on soil moisture distribution across the Canberra region is available in the Australian Landscape Water Balance.

 

Streamflow responses

Map of key gauging stations. Molonglo River at Burbong, station number 410705, is located east of Queanbeyan, upstream of the confluence of the Molonglo and Queanbeyan River. Cotter River at Gingera, station number 410730, is in the west of the region. Queanbeyan River Upstream Googong Dam, station number 410781, is in the central east part of the region.
Figure C5 Key flow gauging stations along the main rivers within the Canberra region

 

  • The Cotter and Queanbeyan rivers contribute most of the inflows to the storages in the Canberra region.
  • Molonglo River, one of the major tributaries of Murrumbidgee River, runs through the Canberra city centre where it is dammed to form Lake Burley Griffin.

 

Figure C6 Total monthly flow for major rivers in the Canberra region during the 2020–21 year compared with the average and percentiles

 

  • Streamflows were above average for most of 2020–21 reflecting the wet conditions experienced across the region. For example, total annual flow in the Queanbeyan River upstream of Googong Dam (Station 410781) was 136 GL compared to the average value of 43 GL.
  • This was the first year of high streamflow in the region's rivers since 2016.
  • Very high streamflow occurred in March 2021 due to heavy rainfall in the latter part of the month. The rainfall caused minor to moderate flooding in some parts of the region (see the Bureau's Special Climate Statement for more information).
  • Streamflow was also high in August and November 2020 following well above-average rainfall over the entire region during August 2020 and October 2020 respectively (see Rainfall).