Check rainfall and dam volumes and find out how declining rainfall is affecting the amount of water (streamflow) flowing into our dams.

Our water overview

Updated: Friday, 26 February 2021 Learn more about how this data is updated

To 9am

0.00

mm

May total

May average*

32.20

mm

88.70

mm

Current

42.5%

268 GL

Last year

45%

284 GL

Change

5.7%

-16.2 GL

* Average monthly rainfall (for the period 1876 - 2016).
Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly.

Perth monthly rainfall totals

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL
2021 0.2 38.6 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 38.8
2020 3.0 33.2 32.6 12.6 110.4 122.8 83.0 92.6 78.6 12.6 90.2 4.4 676.0
Avg 1994 - 2019* 19.7 12.1 19.8 36.8 85.1 130.2 145.3 124.3 82.9 37.9 22.2 10.9 727.2
Avg 1876 - 2016** 9.7 12.5 19.5 44.2 116.9 173.1 167.7 132.9 81.0 51.5 22.4 13.1 844.5
N/A = Data not available. Rainfall measured in mm.
* Average monthly rainfall data supplied by the Bureau of Meteorology for the period 1994 to 2019.
** Average monthly rainfall (for the period 1876 - 2016).

Select each point to see rainfall.

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL
2021 0.2 38.6 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 38.8
2020 3.0 33.2 32.6 12.6 110.4 122.8 83.0 92.6 78.6 12.6 90.2 4.4 676.0
2019 7.2 0.2 6.2 44.2 17.8 212.0 108.6 114.4 31.4 20.2 18.4 2.2 582.8
2018 106.2 0.2 2.6 20.6 67.4 126.4 152.0 186.0 35.2 40.0 3.2 1.8 741.6
Avg 1876 - 2016* 9.7 12.5 19.5 44.2 116.9 173.1 167.7 132.9 81.0 51.5 22.4 13.1 844.5
N/A = Data not available. Storage measured in mm.
* Average monthly rainfall (for the period 1876 - 2016).

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL
2021 0.2 38.8 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 38.8
2020 3.0 36.2 68.8 81.4 191.8 314.6 397.6 490.2 568.8 581.4 671.6 676.0 676.0
2019 7.2 7.4 13.6 57.8 75.6 287.6 396.2 510.6 542.0 562.2 580.6 582.8 582.8
2018 106.2 106.4 109.0 129.6 197.0 323.4 475.4 661.4 696.6 736.6 739.8 741.6 741.6
Avg 1876 - 2016* 9.7 22.2 41.7 85.9 202.8 375.9 543.6 676.5 757.5 809.0 831.4 844.5 844.5
N/A = Data not available. Storage measured in mm.
* Average monthly rainfall (for the period 1876 - 2016).

Year Summer Autumn Winter Spring TOTAL
2021 43.2 0.0 0.0 0.0 43.2
2020 38.4 155.6 298.4 181.4 673.8
2019 9.2 68.2 435.0 70.0 582.4
2018 147.0 90.6 464.4 78.4 780.4
Avg 1876 - 2016* 35.3 180.6 473.7 154.9 844.5
N/A = Data not available. Storage measured in mm.
* Average monthly rainfall (for the period 1876 - 2016).

Perth Historical Rainfall

How climate change is impacting our water sources

Water sources for our largest scheme, the Integrated Water Supply Scheme (IWSS) which supplies Perth, the Goldfields and Agricultural Region and some parts of the South West have changed dramatically. Water for the IWSS is now comprised of a combination of sources, including desalinated seawater, groundwater, groundwater replenishment and streamflow into dams.

Traditionally, Perth relied heavily on streamflow into our dams as a water source, but declining streamflow has meant dams now play a bigger role as storage reservoirs. The water in our dams is no longer just made up of inflows from rain. Groundwater and desalinated water are stored in these dams during periods of low demand so it is available when it is most needed in the hotter months.

How Perth's water sources have changed

In 2019-20 the breakdown of Perth's water sources (IWSS) consisted of:

Desalination icon
%
Desalination
Groundwater icon
%
Groundwater
Dams icon
%
Dams
Groundwater replenishment icon
%
Groundwater replenishment