Gilroy (CA) Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Gilroy, California, United States of America. These values are calculated using 30 years of data (1990–2020) to ensure accuracy. Let's now guide you through the details for a complete overview.

Gilroy typically sees modest rainfall throughout the year, with an average annual precipitation of 428 mm (17 in). The city experiences a distinct dry season during certain months, as illustrated in the graph below.

Monthly Precipitation Levels

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

Gilroy can be quite wet during December, receiving approximately 98 mm (3.9 in) of precipitation over 10 rainy days.

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

December, the wettest month, has a maximum daytime temperature of 16°C (61°F). During the driest month July you can expect a temperature of 30°C (86°F). For more detailed insights into the city's temperatures, visit our Gilroy Temperature page.

Gilroy's average annual precipitation is 428 mm (17 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.

Beijing, China, receives 560 mm (22 in) of annual precipitation, concentrated in the summer months.

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

Ho Chi Minh City, Vietnam, receives 1955 mm (77 in) of annual rainfall, with a pronounced wet season from May to November, typical of its tropical monsoon climate.

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 Gilroy (CA):

• 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.

• The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
• Approximately 70% of lightning bolts strike land rather than oceans.
• A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.

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