Half Moon Bay (CA) Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Half Moon Bay (CA). The numbers are calculated over a 30-year period to provide a reliable average. Let's now guide you through the details for a complete overview.

Generally, Half Moon Bay has a moderate amount of precipitation, averaging 625 mm of rainfall annually.

Monthly Precipitation Levels

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

The climate in Half Moon Bay shows significant variation throughout the year. Expect 144 mm of precipitation during the wettest month December, distributed over 14 rainy days.

In contrast, July offers drier and sunnier days, with around 3 mm of rainfall over 5 rainy days.

December, the city’s wettest month, has a maximum daytime temperature of 15°C and receives 160 hours of sunshine. During the driest month July you can expect a temperature of 21°C. For more detailed insights into the city’s temperatures, visit our Half Moon Bay Temperature page.

Annual Precipitation in the United States of America

The map below shows the annual precipitation across the United States of America. You can also select the different months in case you are interested in a specific month.

Amsterdam Precipitation Compared World Wide

Half Moon Bay’s average annual precipitation is 625 mm. Let’s compare this to some popular worldwide tourist destinations:

Boston, USA, experiences 1238 mm of annual precipitation, including significant snowfall during the winter.

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

Perth, Australia, receives 565 mm of rainfall annually, mostly during the winter months.

Bangkok, Thailand, experiences a tropical monsoon climate with 1668 mm of annual rainfall, with the heaviest precipitation occurring during September and October.

How is Precipitation Measured?

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.

Interesting weather facts

• Mawsynram in India is noted as being the wettest place on earth, with over 11 meters of rain falling every year.
• In contrast, Antofagasta in Chile is among the driest places on the planet, getting less than 0.1mm 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 Half Moon Bay (CA)’s weather, including sunshine hours, humidity levels, and temperature data, visit our Half Moon Bay (CA) Climate page.