San Mateo Temperature by Month
The average annual maximum temperature in San Mateo, Alajuela, Costa Rica is 29°C (84°F), with little variation between seasons. This page covers monthly averages, day-night differences, and how San Mateo compares to cities worldwide.
San Mateo Monthly Temperatures
In San Mateo temperatures are generally consistent throughout the year. Maximum daytime temperatures range from a comfortable 28°C (82°F) in October to a very warm 31°C (88°F) in March. Nighttime lows range from 21°C (70°F) in March to 21°C (70°F) in October.
The chart below illustrates the average maximum day and minimum night temperatures in San Mateo by month:
Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM. March, the city's warmest month, sees 282 hours of sunshine.
The chart below shows the average temperature throughout the year:
Daily Historical Temperatures
44-year average (1976-2025)
Average high and low temperatures for each day of the month based on long-term records.
Average temperatures in July
Historical San Mateo Temperatures: 1976-2026
Browse day-by-day temperature records for San Mateo spanning 51 years. Select any month and year to see actual high and low temperatures recorded on each day.
Temperature: San Mateo vs Costa Rica
The map below shows the annual temperature across Costa Rica. You can also select individual months if you want to compare a specific time of year.
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moderate
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San Mateo vs World: Temperature Compared
San Mateo's average annual maximum temperature is 29°C (84°F). To put that in context, here's how it compares to a few well-known destinations:
Barcelona, Spain has an annual average of around 21°C (70°F), with warm summers and mild, fairly short winters.
Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.
Boston, USA averages 16°C (61°F) annually, with four distinct seasons and cold winters that rival northern Europe.
Adelaide, Australia averages 21°C (70°F) a year, with warm summers, mild winters, and relatively low rainfall year-round.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round — large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.
For more on San Mateo's weather — including monthly rainfall, sunshine hours, and humidity — visit our San Mateo climate page.
