Derby Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Derby, Western Australia, Australia. The figures are based on a 30-year period (1990–2020) to provide a reliable average. Now, let's explore all the details to give you a full picture.

Generally, Derby experiences moderate precipitation patterns, averaging 729 mm (29 in) yearly. However, this average masks significant seasonal variation, including a distinct dry season during certain months that are clearly visible in our monthly breakdown below.

Monthly Precipitation Levels

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

Derby can be quite wet during January, receiving approximately 215 mm (8.5 in) of precipitation over 11 rainy days.

In contrast September, experiences much drier conditions, with 0.2 mm (0.01 in) of rainfall, spread across 0 rainy days.

January, the wettest month, has a maximum daytime temperature of 34°C (93°F). During the driest month September you can expect a temperature of 33°C (91°F). For more detailed insights into the city's temperatures, visit our Derby Temperature page.

Derby's average annual precipitation is 729 mm (29 in). Let's compare this to some popular worldwide tourist destinations:

In Lisbon, Portugal, the average annual precipitation is 774 mm (30 in), characterized by wet winters and dry summers typical of the Mediterranean climate.

In Seoul, South Korea, the average annual precipitation is 1237 mm (49 in), with most rain falling during the summer monsoon season.

In Tokyo, Japan, the average annual precipitation is 1528 mm (60 in), with significant summer rains due to typhoon season.

Mumbai, India, experiences a tropical monsoon climate with 1860 mm (73 in) of annual rainfall, with the majority of precipitation happening during the monsoon season from June to September.

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.

The proximity of a location to a large body of water can significantly affect its rainfall patterns:

• Ocean Influence: Coastal regions typically receive more rainfall due to the presence of moisture-laden winds from the ocean. These regions tend to have more humid climates and experience more frequent precipitation, especially in winter.
• Continental Climates: Areas further from the sea, such as inland or continental regions, experience less frequent rainfall and more extreme seasonal variations in precipitation.

• Mawsynram in India is noted as being the wettest place on earth, with over 11 meters (36 feet) of rain falling every year.
• In contrast, Antofagasta in Chile is among the driest places on the planet, getting less than 0.1mm (0.004 inches) per year, with some years recording virtually no rainfall.
• Nearly 1,650 thunderstorm cells are estimated over the planet at any given time.

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