You're planning a trip to the Alamo City. You've heard about the River Walk, the history, and the tacos. But then you look at the forecast for March and see a messy mix of numbers that don't quite make sense. Is it 50 degrees? Is it 80? Honestly, it's often both in the same afternoon.
Weather in march in san antonio texas is the ultimate meteorological identity crisis. It's that weird transition where the stubborn South Texas winter tries to hang on while the spring sun is already demanding its time in the spotlight. If you’re coming for Spring Break or just to see the Bluebonnets, you need to know that "averages" are kinda lying to you.
The Temperature Rollercoaster Is Real
On paper, the city looks perfect. The National Weather Service records show an average high of 75°F and an average low of 54°F. That sounds like a dream, right? Perfect t-shirt weather.
But here’s the reality: South Texas doesn't do "average."
You might wake up to a damp, foggy 50°F morning that feels like the Pacific Northwest. By 2:00 PM, the clouds break, the humidity drops, and suddenly you’re sweating in 82°F heat under a high UV index. Then, a "Blue Norther" cold front sweeps through at dinner time, and you're hunting for a parka because the temperature just cratered 20 degrees in two hours. This isn't an exaggeration; it’s a Tuesday in Bexar County.
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Humidity and the "Feel" of March
People talk about Texas humidity like it’s a summer-only problem. In March, San Antonio hits a relative humidity average of about 69%.
Because the air is cooler than in August, it doesn't feel like a steam room. Instead, it feels heavy and misty. It’s why those 55-degree mornings feel so much "colder" than a dry 55 in Arizona. That dampness clings to your skin. When the sun finally pops out, that humidity helps the heat feel more intense.
- Morning: Thick fog or "mizzle" (mist/drizzle).
- Afternoon: Clear, crisp, and surprisingly bright.
- Evening: Quick cooling as soon as the sun dips.
Why the Wind Matters
March is actually one of the windiest months in the region, second only to April. You’re looking at average speeds of 15.1 mph. While that sounds like a nice breeze, it’s often coming from the south, bringing up that moist Gulf air. If it switches to the north, it’s a biting wind that makes outdoor dining at the Pearl District a lot less romantic if you’re underdressed.
Rainfall and Spring Storms
Don't let the "dry Texas" reputation fool you. While March isn't the wettest month—that honor usually goes to May—it still sees about 2 to 3 inches of rain on average.
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The rain here doesn't usually linger for days. It’s more about the "pop-up" variety. You’ll get a localized downpour that lasts 20 minutes and floods a street corner, and then the sun comes out like nothing happened. The probability of rain on any given day sits around 18% to 23%. Basically, carry a small umbrella in your bag, but don't plan your whole life around it.
The Severe Weather Wildcard
We have to talk about the "S" word: Storms. March is the start of severe weather season. While tornadic activity is rare right in the city, lightning and hail are very real possibilities. The TPC San Antonio, home to the Valero Texas Open, has seen its fair share of weather delays because of these quick-moving spring cells. If the sky turns a weird shade of bruised purple-green, head inside.
What to Actually Pack (The Survival List)
Forget a "capsule wardrobe." You need a "survival kit." Since you'll be walking the River Walk or exploring the Missions, comfort is king, but versatility is the god it serves.
- The Base Layer: Short-sleeve cotton or linen. You will want this at 3:00 PM.
- The Mid Layer: A light hoodie or a denim jacket.
- The "Oh No" Layer: A packable windbreaker or light rain shell.
- Footwear: Flats or sneakers. The River Walk's stone paths are slippery when damp and unforgiving on heels.
- Sun Protection: The UV index hits 8 (Very High) in March. Even if it’s 65 degrees, you will get a "San Antonio Sunburn" if you’re outside for three hours without SPF.
Events Affected by the Elements
March is prime time for the San Antonio Zoo and the Botanical Gardens. The animals are active because it’s not 105 degrees yet.
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If you’re here for St. Patrick’s Day, they dye the river green. It’s a blast, but it’s often overcast. If you’re lucky enough to be here when the wildflowers peak, the Texas Hill Country (just a 30-minute drive north) is stunning. However, the weather that makes flowers bloom also makes allergies explode. If you suffer from "Cedar Fever" or oak pollen allergies, bring your meds. March in San Antonio is a pollen nightmare.
Actionable Steps for Your March Visit
Stop checking the 14-day forecast two weeks out. It’s useless here. Instead, follow these three rules:
- Check the "RealFeel": The temperature might say 70, but if the humidity is high and the wind is 20 mph, it will feel like 60. Use a weather app that calculates the dew point and wind chill.
- Hydrate Early: The dry air behind cold fronts can dehydrate you just as fast as the summer heat. Drink water even if you aren't sweating.
- Book Outdoor Tours for Mornings: If you're doing the Missions or the Zoo, go at 9:00 AM. You beat the afternoon heat and the highest UV exposure.
Basically, enjoy the chaos. March is the last time San Antonio is truly comfortable before the "unrelenting oven" of summer kicks in. Grab a margarita, wear your layers, and watch the clouds roll by.