San Juan Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in San Juan. The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s break down all the details for a clearer picture.

San Juan has a notably wet climate with abundant precipitation, recording 1164 mm of rainfall per year.

Monthly Precipitation Levels

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

San Juan can be quite wet during August, receiving approximately 156 mm of precipitation over 22 rainy days.

In contrast March, experiences much drier conditions, with 32 mm of rainfall, spread across 9 rainy days.

August, the city’s wettest month, has a maximum daytime temperature of 30°C. During the driest month March you can expect a temperature of 29°C. For more detailed insights into the city’s temperatures, visit our San Juan Temperature page.

Annual Precipitation in Trinidad & Tobago

The map below shows the annual precipitation across Trinidad & Tobago. You can also select the different months in case you are interested in a specific month.

Amsterdam Precipitation Compared World Wide

San Juan’s average annual precipitation is 1164 mm. Let’s compare this to some popular worldwide tourist destinations:

In Barcelona, Spain, the average annual precipitation is 644 mm, evenly distributed across the year with no extreme wet or dry seasons.

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

In Brisbane, Australia, the annual precipitation is 979 mm, making it wetter than Sydney.

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

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.

How Does Precipitation Affect Local Climate?

Precipitation has a very strong role in determining the local climate and ecosystem:

• Rainy Seasons: Many parts of the world have well-defined wet seasons where precipitation is distinctly higher. These are normally accompanied by lush vegetation and temperature patterns.
• Dry Seasons: In areas where the climate is either desert or Mediterranean, the amount of precipitation is drastically reduced, leading to a shortage of water and arid conditions.

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