UV Index
UV Index
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Today's UV index in San Antonio, United States 
will be up to 4.8, indicating a moderate level of sun exposure for the average person. Check the annual sun radiation in the city and our tips for today to make sure you're safe in the sun.
With a UV index reaching up to 4.8 in San Antonio, stay shaded during midday when the sun is strongest; wear protective clothing, a wide-brimmed hat, UV-blocking sunglasses; apply SPF 30+ sunscreen every 2 hours, even on cloudy days; and be cautious of heightened UV on bright surfaces.
San Antonio's UV index is typically high, with an average annual value of 9.4, indicating a very high risk of harm from unprotected sun exposure. The city's subtropical climate means intense sunlight is prevalent throughout the year.
San Antonio has a distinct seasonal pattern, with mild winters (December to February), hot summers (June to August), and a brief spring and autumn. Temperatures often soar above 100°F (38°C) during the summer months, while winters rarely dip below freezing.
Compared to neighboring cities and countries, San Antonio's climate is relatively hot and humid. It's drier than neighboring Houston, but more humid than cities in the Southwest. Mexico's climate is similar, with a mix of desert and subtropical regions, while the Gulf Coast region is generally more humid and prone to hurricanes.
The chart below displays the average Shortwave Radiation Sum (MJ/m²) for each month of the last year in San Antonio. It's designed to provide you with a better understanding of the yearly weather and sun exposure.