San Mateo Monthly Rainfall & Precipitation
This page shows both the average monthly rainfall and the number of rainy days in San Mateo, Alajuela, Costa Rica. These averages rely on historical data collected over 30 years, from 1990 to 2020. Let's explore the details to provide you with a complete overview.
San Mateo has a relatively rainy climate with high precipitation levels, averaging 3695 mm (145 in) of rainfall annually. Despite the high annual total, it does experience a distinct rainy season during certain months. Examine our detailed charts below to understand these seasonal patterns.
Monthly Precipitation Levels
The average number of days each month with precipitation (> 0.2 mm (0.01 in))
San Mateo can be quite wet during October, receiving approximately 548 mm (22 in) of precipitation over 22 rainy days.
In contrast February, experiences much drier conditions, with 38 mm (1.5 in) of rainfall, spread across 7 rainy days.
October, the wettest month, has a maximum daytime temperature of 28°C (82°F). The city receives 167 hours of sunshine in this period. During the driest month February you can expect a temperature of 31°C (88°F). For more detailed insights into the city's temperatures, visit our San Mateo Temperature page.
Daily Historical Precipitation
42-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in June
Explore San Mateo's Historical Precipitation: 1976-2026
Browse day-by-day precipitation records for San Mateo spanning 51 years. Select any month and year to see actual rainfall and snowfall recorded on each day.
Annual Rainfall in Costa Rica: City Comparison
The map below shows the annual precipitation across Costa Rica. You can also select the different months in case you are interested in a specific month.
heavy rainfall
high
moderate
low
almost none
San Mateo vs World: Rainfall Compared
San Mateo's average annual precipitation is 3695 mm (145 in). Let's compare this to some popular worldwide tourist destinations:
Seville, Spain, experiences 541 mm (21 in) of rainfall annually, with wet winters and dry summers typical of southern Spain.
In Shanghai, China, the annual average precipitation is 1347 mm (53 in), with a humid subtropical climate.
In Brisbane, Australia, the annual precipitation is 979 mm (39 in), making it wetter than Sydney.
Kuala Lumpur, Malaysia, receives 2529 mm (100 in) of annual rainfall, characteristic of its equatorial tropical rainforest climate, with consistent rainfall throughout the year and peak months during March and November.
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 San Mateo:
- 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.
- 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 San Mateo's weather, including sunshine hours, humidity levels, and temperature data, visit our San Mateo Climate page.
