Weather in San Antonio: Climate, Seasons, and Average Monthly Temperature

The top attractions for most San Antonio visitors are outdoors: the Alamo and the rest of the UNESCO World Heritage designated missions, the River Walk, and the Mercado or Market Square shopping district. 

Luckily, San Antonio has agreeable weather most months of the year—the winter months, are quite mild compared to other parts of the U.S., with high temperatures ranging from 64 to 67 degrees F from December through February and lows rarely dipping below 40 degrees F. 

The summers can be sweltering, however, with heat and humidity on the rise from June through September. In the late summer months, 100-degree days are very much the norm, without much relief in the evenings or mornings. Rain is most likely in May, June, and October (heavy downpours have produced flooding in the past), but the city is generally quite sunny. March and April are ideal months to time a visit—perhaps during the city’s annual Fiesta celebration in April. 

Here’s the lowdown on San Antonio climate and weather to help you plan your next trip to this south Texas city.

Fast Climate Facts 

• Hottest Month: August (97 F / 36 C)
• Coldest Month: January (64 F / 18 C)
• Wettest Month: June (4.7 inches of rainfall average)
• Sunniest Month: July (10 hours average sunshine)
• Best Month for Walking or Biking on the River Walk: April (81 F / 27 C)

Urgent Seasonal Information 

San Antonio is one of the most flood-prone areas of North America, according to the San Antonio River Authority and is part of an area that is termed “flash flood alley.” Exercise caution when visiting during the rainy spring months—and never attempt to drive through low water crossings by heeding the National Weather Service’s caution: “Turn around, don’t drown.”

Winter in San Antonio

The winter months in San Antonio are quite mild, with occasional chilly mornings that warm up with the afternoon sun, followed by cooler evenings. Following the holidays, these months are typically slower for tourist season and can be a great time of year to visit some of the most popular attractions and avoid the crowds.

Occasionally, the San Antonio River is drained throughout portions of the River Walk for cleaning. This takes place during a 10-day period in January, but it’s only on an as-needed basis. Check in advance of your trip if this would affect your plans. 

What to pack: Layered clothing, giving you options with short sleeves for warm days, plus light sweaters and jackets, should be all you’ll need to enjoy the winter months. You might wish to pack a coat just in case temperatures are cooler than normal.

Average Temperatures by Month

• December: 64 F (18 C) / 42 F (6 C)
• January: 63 F (17 C) / 41 F (5 C)
• February: 67 F (19 C) / 44 F (7 C)

Spring in San Antonio

Spring is a lovely time to visit south Texas, and early spring (starting even as soon as February) ushers in the bloom of Texas wildflowers throughout San Antonio’s parks and along the highways. In April, San Antonio celebrates Fiesta across the city, which brings large crowds in for parties and parades (including a nighttime boat parade on the river).

Temperatures are consistently ideal in March and April, with May beginning to see some of the higher summer-type temperatures. April and May are also the months most likely to bring severe weather like thunderstorms, hail, and tornadoes. 

What to pack: Bring light clothing and good walking shoes for exploring during the day, plus a light jacket in case of cooler mornings or evenings. It’s also a good idea to pack a rain poncho and umbrella.

Average Temperatures by Month

• March: 74 F (23 C) / 51 F (11 C)
• April: 81 F (27 C) / 58 F (14 C)
• May: 87 F (31 C) / 67 F (19 C)

Summer in San Antonio

Although the hot summer months are not ideal times to visit San Antonio for people who are heat-averse, many people still travel here during this time and enjoy the hot, dry climate. There are plenty of air-conditioned museums and other attractions, plus waterparks in the area where you can keep cool.

Peak summer heat will occur in the later months, especially in August and even into September. Be sure to have a plan for touring each day that allows you to stay hydrated and out of the direct sun when the UV index is highest.

What to pack: June temperatures may still remain relatively mild, but for most of the summer in San Antonio, shorts and short-sleeved shirts or tank tops are all you’ll need. Don’t forget to bring your sunscreen, sunhat, sunglasses and a water bottle for staying hydrated throughout the day. 

Average Temperatures by Month

• June: 92 F (33 C) / 73 F (23 C)
• July: 95 F (35 C) / 75 F (24 C)
• August: 96 F (36 C) / 75 F (24 C)
• September: 90 F (32 C) / 69 F (21 C)

Fall in San Antonio

Although other parts of the U.S. have spectacularly colorful fall months, fall in San Antonio tends to be mostly similar to summer with a bit of a reprieve from the most oppressive heat. As such, it tends to be another ideal time to visit the city.

You won’t find much leaf-peeping; the palm tree fronds and other leaves stay green year-round. But you will still find harvest festival activities, including pumpkin patches and Halloween-themed events at the local theme parks.

What to pack: Prepare for mild to hot temperatures by packing light clothing, with layered options in case of cooler temperatures in this shoulder season. A light jacket should suffice, as well as rain gear.

Average Temperatures by Month

• October: 82 F (28 C) / 60 F (16 C)
• November: 72 F (22 C) / 50 F (10 C)

San Antonio receives an average amount of rainfall per year, very rarely snows, and is slightly sunnier than average compared to other cities in the U.S. Bring your sunglasses regardless of the time of year.