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.

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:

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.