Climate Insights for San Marcos

The climate in San Marcos is temperate. The average annual temperature is 18°C and approximately 414mm of precipitation falls per year. January is the wettest month, receiving around 83mm of rainfall. San Marcos is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: August, July, September. The coldest months are January, February, December, when temperatures can drop to 9°C.

San Marcos sees moderate temperature variation throughout the year, ranging from 9°C to 29°C. The warmest month is August, when average highs reach 29°C and the mean temperature sits around 23°C. January is the coolest month, with minimum temperatures around 9°C and an average of 13°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between October and November, with a 4°C shift in average temperatures.

San Marcos is a relatively dry area, receiving approximately 414mm of precipitation annually, which averages out to around 34mm per month. The wettest month is January, averaging 83mm of rainfall. March and February also tend to see above-average precipitation. The driest month is July, with just 2mm. That's 81mm less than January, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

San Marcos is relatively calm, with an average annual wind speed of 7km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is May, averaging 8km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 6km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.

It is currently summer in San Marcos, which began on June 21, 2026. San Marcos is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in August at around 29°C, while the coldest stretch bottoms out in January near 9°C. Autumn is next, beginning on September 23, 2026 (7 days from now).

The best time to visit San Marcos is during April, May, June, July, August, September, October and November, when the weather is most comfortable for travellers. During these months, average temperatures hover around 20°C with modest rainfall averaging 14mm per month. By contrast, January can be quite cold with temperatures dropping to 9°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for San Marcos based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.