Climate Insights for San Antonio

The climate in San Antonio is temperate. The average annual temperature is 18°C and approximately 2465mm of precipitation falls per year. San Antonio receives a notable amount of rainfall throughout the year, including during its driest month. San Antonio sits near the equator, so seasonal temperature differences are minimal throughout the year.

San Antonio sees moderate temperature variation throughout the year, ranging from 13°C to 25°C. September is the warmest month, though highs remain moderate at 25°C with a mean of 19°C. January is the coolest month, with minimum temperatures around 13°C and an average of 17°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs.

San Antonio is a very wet location, receiving approximately 2465mm of precipitation annually, which averages out to around 205mm per month. The wettest month is November, averaging 436mm of rainfall. March and April also tend to see above-average precipitation. The driest month is August, with just 43mm. That's 393mm less than November, 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 Antonio is relatively calm, with an average annual wind speed of 9km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is August, averaging 11km/h, though still comfortable for most outdoor activities. The calmest conditions occur in November, with average winds dropping to 7km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 4km/h gap between the calmest and windiest months.

It is currently spring in San Antonio, which began on March 20, 2026. San Antonio sits near the equator, so the traditional four-season cycle is less pronounced — temperatures remain relatively stable year-round. The warmest period peaks in September at around 25°C, while the coldest stretch bottoms out in January near 13°C. Summer is next, beginning on June 21, 2026 — 88 days from now.

The best time to visit San Antonio is during July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 51mm per month. By contrast, January can be quite cold with temperatures dropping to 13°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for San Antonio 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.