Perth Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Perth, Western Australia, Australia. These values are calculated using 30 years of data (1990–2020) to ensure accuracy. Now, let's explore all the details to give you a full picture.

Generally, Perth receives mid-range precipitation levels, with 565 mm (22 in) annually. The distribution varies significantly throughout the year, with a distinct dry season during certain months, as shown in our charts below.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

The climate in Perth shows significant variation throughout the year. Expect 100 mm (3.9 in) of precipitation during the wettest month July, distributed over 15 rainy days.

In contrast, December offers drier and sunnier days, with around 12 mm (0.5 in) of rainfall over 4 rainy days.

July, the wettest month, has a maximum daytime temperature of 18°C (64°F). The city receives 191 hours of sunshine in this period. During the driest month December you can expect a temperature of 30°C (86°F). For more detailed insights into the city's temperatures, visit our Perth Temperature page.

Perth's average annual precipitation is 565 mm (22 in). Let's compare this to some popular worldwide tourist destinations:

Chicago, USA, sees an annual precipitation of 1062 mm (42 in), with rain and snow contributing to its humid climate.

Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with 1000 mm (39 in) of annual rainfall, mostly in the summer.

Melbourne, Australia, has 690 mm (27 in) of rainfall annually, spread fairly evenly throughout the year.

Kuala Lumpur, Malaysia, receives 2529 mm (100 in) of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Climate change is affecting precipitation patterns worldwide, including Perth:

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

• "Ginger" was the longest-lasting Atlantic tropical storm, which spun around the open ocean for 28 days in 1971.
• The world's largest snowflake was recorded in the Guinness Book of Records, at 38 cm (15 inches) wide and 20 cm (7.9 inches) thick. The snowflake fell at Fort Keogh, Montana, USA, on 28 January 1887.
• The greatest snowfall recorded was on Mt. Rainier, Washington State, USA, over 31.5 meters (103 feet) fell during the winter of 1972.

For more detailed information about Perth's weather, including sunshine hours, humidity levels, and temperature data, visit our Perth Climate page.