Canberra: Climate and water
- Total annual rainfall was below average across the region for the third consecutive year.
- Streamflows were very low reflecting the below-average rainfall and poor soil moisture conditions.
- Annual streamflow in the Queanbeyan River was the lowest in 10 years.
For further information on the region's climate and water conditions during the 2018–19 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 2018–19 year
- Total area-averaged rainfall for the year was 626 mm, below the mean value of 784 mm.
- Rainfall was very low during July 2018 and April 2019 across almost the entire region.
- The below-average rainfall throughout the spring 2018 and winter 2019 months was likely due to a positive phase of the Indian Ocean Dipole that influenced Australia's climate during those periods (see the Bureau's 2018–19 Climate Report for more information).
- Rainfall was above average across the entire region in December 2018 and March 2019.
Figure C2 Total monthly rainfall for the Canberra region during the 2018–19 year compared with the average and percentiles for the region
- Rainfall was only above average in December 2018 and March 2019. All other months had average to below-average rainfall.
- In July 2018, rainfall was below the 10th percentile and was the driest July since 1995.
Actual evapotranspiration
Figure C3 Annual and monthly actual evapotranspiration for the Canberra region during the 2018–19 year
- Total area-averaged actual evapotranspiration was average to below average across the region.
- Well below-average evapotranspiration occurred during the 5-month period between July–November 2018, reflecting the dry conditions and low water availability across the region throughout that period.
- Evapotranspiration was high during December 2018–January 2019 due to the increased water availability following above-average rainfall in December 2018.
Soil moisture
Figure C4 Annual and monthly soil moisture deciles for the Canberra region during the 2018–19 year
- Soil moisture in the root zone (0–1 m depth) was well below average across most of the region; some central areas experienced their poorest soil moisture conditions on record.
- Rainfall and soil moisture are typically closely aligned. For example, below-average soil moisture conditions across the entire region during the 5-month period from July–November 2018 is due to the low rainfall that occurred during most of that period.
- Soil moisture conditions in December 2018 were average to above average following the high rainfall during that month.
- More information on soil moisture distribution across the Canberra region is available in the Australian Landscape Water Balance.
Streamflow responses
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 2018–19 year compared with average and percentiles
- Streamflows were well below average for most of the year, which reflects the relatively low rainfall and very poor soil moisture conditions experienced across the region.
- Total annual flow in the Queanbeyan River upstream of Googong Dam (Station 410781) was 5 GL compared to the average value of 41 GL. This was the third lowest on record and the lowest in 10 years.
- The high rainfall during December 2018 had only a minor effect on streamflow in these rivers. The very dry soil moisture conditions across the region during the preceding winter–spring months meant much of the rainfall that occurred was soaked up by the soil.