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

Dam volumes, rainfall and water use data is updated every working day, streamflow is updated weekly. Learn more about how this data is updated.

Our water overview

Updated: Wednesday, 30 September 2020

Current

42.5%

268 GL

Last year

45%

284 GL

Change

5.7%

-16.2 GL

To 9am

0.00

mm

May total

May average*

32.20

mm

88.70

mm

* Average monthly rainfall (for the period 1876 - 2016).

Perth monthly rainfall totals

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL
2020 3.0 33.2 32.6 12.6 110.4 122.8 83.0 92.6 78.6 N/A N/A N/A 568.8
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
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
2020 3.0 33.2 32.6 12.6 110.4 122.8 83.0 92.6 78.6 N/A N/A N/A 568.8
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
2017 45.4 137.2 23.6 0.0 70.8 88.0 172.6 151.6 77.4 42.0 4.8 40.6 854.0
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
2020 3.0 36.2 68.8 81.4 191.8 314.6 397.6 490.2 568.8 N/A N/A N/A 568.8
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
2017 45.4 182.6 206.2 206.2 277.0 365.0 537.6 689.2 766.6 808.6 813.4 854.0 854.0
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
2020 38.4 155.6 298.4 78.6 571.0
2019 9.2 68.2 435.0 70.0 582.4
2018 147.0 90.6 464.4 78.4 780.4
2017 192.8 94.4 412.2 124.2 823.6
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 has impacted our water sources

Water sources for our largest scheme, the Integrated Water Supply Scheme (IWSS), 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.

See how our climate has changed

In 2019-20 the breakdown of our IWSS water sources consisted of:

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