San Juan Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in San Juan, San Juan Province, Argentina. These averages rely on historical data collected over 30 years, from 1990 to 2020. Now, let's explore all the details to give you a full picture.

With annual rain/snowfall averaging 324 mm (13 in), San Juan maintains relatively low precipitation levels throughout the seasons. However, it does have a distinct dry season during certain months, creating distinct patterns as demonstrated in our detailed graph below.

Monthly Precipitation Levels

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

The climate in San Juan shows significant variation throughout the year. Expect 40 mm (1.6 in) of precipitation during the wettest month December, distributed over 4 rainy days.

In contrast, June offers drier and sunnier days, with around 12 mm (0.5 in) of rainfall over a single rainy day.

December, the wettest month, has a maximum daytime temperature of 32°C (90°F). The city receives 350 hours of sunshine in this period. During the driest month June you can expect a temperature of 18°C (64°F). For more detailed insights into the city's temperatures, visit our San Juan Temperature page.

San Juan's average annual precipitation is 324 mm (13 in). Let's compare this to some popular worldwide tourist destinations:

The city of Rome, Italy, has an average annual precipitation of 832 mm (33 in), spread fairly evenly throughout the year.

Osaka, Japan, experiences 1507 mm (59 in) of rainfall annually, spread across the year with wetter summers.

In Brisbane, Australia, the annual precipitation is 979 mm (39 in), making it wetter than Sydney.

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.

• "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 San Juan's weather, including sunshine hours, humidity levels, and temperature data, visit our San Juan Climate page.