A few weeks ago, I was working outside my Austin home on a rainwater-catchment system—I’m one of those incorrigible weekend warrior DIYers who keeps Home Depot in business—when I noticed I was completely drenched in sweat. It was midmorning in May, in the shade, still hours away from the peak heat of the day. I was just tinkering with little irrigation parts, not doing anything as laborious as the ditchdigging and stonemasonry that had occupied my winter and spring. Yet the air felt as if it could be wrung out, a soupy, hot mess you might expect in Dubai—or Houston. Not that I was surprised. The sticky heat now seems inescapable for long stretches of the year. Biking around town, picking tomatoes in the garden, walking from the house to the car—just being outside is an exercise in swimming through liquid air. And my outdoor activities are all essentially optional, unlike those of the legions of Texans who work outside to make a living.
Even during last summer’s brutally hot, dry months—we had 42 days of temps 105 degrees Fahrenheit or higher in Austin—when water was as scarce as a Cybertruck without a vanity license plate, the air somehow still seemed saturated. As a lifelong South and Central Texan, I know not to expect a dry heat. Tucson this isn’t. But recent late springs and summers had just felt different: hotter, yes, but also more humid. Was I right? Or had I just gone soft?
I called Victor Murphy, a Fort Worth–based meteorologist with the National Weather Service, to ask him about my hunch. “You are not imagining things,” he told me. “Dew point temperatures are indeed rising across Texas.” The reasons are fairly simple. Due to the relentless emission of carbon pollution, the planet is heating up, and warmer air tends to contain more moisture. Higher temperatures and higher humidity translate into higher heat indexes, those “feels like” temperatures that represent how we experience weather. Texas is getting more humid.
For the Austin–San Antonio area, the average summer dew point temperature—a good proxy for what we commonly call humidity—has increased by 3.13 degrees since 1940. Murphy said he was surprised to discover that May and June are the most humid months of the year in Austin, Dallas–Fort Worth, Houston, and San Antonio. Though the dreaded heat dome has rarely set in by then, early summer tends to bring lots of thunderstorms. Soggy skies and saturated soil help drive up the heat index. And it’s getting worse. For the eastern third of Texas—from roughly Eagle Pass north to Denton, an area that includes all of our major cities except El Paso—this May was “far and away, head and shoulders” the most humid May on record since 1940, when the National Weather Service began keeping track.
Dew point temperatures were running 6 degrees F above normal. On June 4, San Antonio set an all-time record heat index of 117 degrees, even though the air temperature was “only” 100.4. “So yeah, it was definitely soupy this year,” Murphy said. I can attest: I spent a weekend in Galveston in early June, and one morning the heat index was 99 at 9 a.m. The Gulf giveth—by cooling us with that refreshing onshore breeze—and it taketh away: by delivering the record-hot sea-surface temperatures that are fueling a potentially monster hurricane season and turning southeast Texas into a sauna.
If you’ve lived in Austin, San Antonio, or the Hill Country for any period of time, you’ll often hear people say something like, “Yeah, it’s humid, but at least it’s not Houston.” I’ve got bad news: Central Texas is actually catching up to Houston in terms of humidity. Murphy, that prophet of doom, crunched the numbers, and they are moist. The Houston region’s average summer dew point increased 2 degrees—from 69.5 to 71.5—between 1940 and 2023. But the Austin–San Antonio region’s dew point increased about 3 degrees during that same time period, from 64.5 to 67.5. So while Central Texas is still less humid, we’re catching up! Hey, at least we have swimming holes. Given this disturbing news, Austin meteorologist Avery Tomasco has proposed a new tier on the Muggy Meter:
Okay, but what about when August rolls around and it’s eleventy-billion degrees in the shade and hasn’t rained in three months? At least then the humidity will drop, right? The good news is that the “feels like” temperatures do tend to be lower in late summer. The bad news (“I’ll save the worst for last” is how Murphy prefaced it) is that even our droughts are now much more humid than they used to be. Summer 2023, the second-hottest on record for Texas, had merely average humidity, which sounds tolerable, until Murphy points out that 1956 and 2011, two very hot summers, actually featured a dry heat, with very low average dew points. “Today’s drought and heat is far different than that of the 1950s,” he said.
As for me, I’m trying to adapt. When I work outside, I drink plenty of water and electrolytes. I wear a lightweight sun hoodie, and I sometimes use a portable fan. I take frequent breaks, and, on those days when the heat index hits fever-swamp levels, I plan for what I call a three-shower day.
