Weather in San Antonio in August

A hard month. August asks something of you. Go in knowing what. Daytime highs average 36.7 °C and the afternoon is not negotiable — outdoor plans move to early morning or evening.

August ranks 11 of 12 — near the bottom of San Antonio's year. February is the month that works, and the swing between the two is 48 points, which is a different holiday rather than a slightly better one.

Rain on 7 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for heat management rather than style: shade, water, and a schedule that gives up on the middle of the day.

What the averages hide

Averages flatten a month, and this one hides a few things: 22 days of the month clear 35 °C — that is not a heatwave, it is the month. Across the twenty years measured, the hottest August day reached 45.1 °C and the coldest night fell to 18.9 °C, and the wettest single day dropped 80 mm — roughly 129% of the month's rain in one day.

This is the volatile part. August rainfall has ranged from 3 mm to 206 mm across the twenty years measured — a 203 mm spread around an average of 62 mm. The average is real but almost no individual August looks like it, so treat the figure as the middle of a wide range rather than a forecast.

Wind is light at 9.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 61%.

How August sits in the year

Temperatures hold steady either side: 35.9 °C in July, 36.7 here, 32.8 in September. Nothing about the timing within the month matters much.

Daylight in August

13.2 hours of daylight, losing 0.7 hours across the month. That is between San Antonio's extremes of 14 and 10.3 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 31.5 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

August in San Antonio versus nearby

If San Antonio is one option among several, the nearby comparison is worth making. Corpus Christi is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Laredo is the weaker option in August — within a degree on temperature, 1 day less rain.

So: August is a compromise. February is 47 points better and is what San Antonio is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in San Antonio

See all twelve months in San Antonio, or where else to go in August.