How A Wet Spring Means A Cooler Summer For Austin

Jul 2, 2019

You might have noticed the weather’s been cooler this year in Austin, at least relatively speaking. After all, it’s July and Austin hasn’t hit 100 degrees yet.

A lot of that is because of the wet spring we've had and, meteorologists say, the rain may help us keep off the worst of the summer heat a little while longer.

Blame It On The Rain

To understand how rain means cooler weather, you need to understand how the air heats up in the first place. It’s a little more complicated than the sun heating the air, says Spectrum News Chief Meteorologist Burton Fitzsimmons.

“The sun does not directly heat the air around us,” he says. "The sun heats the ground. The ground then radiates out waves that heat the air.”

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Now, imagine the sun’s rays hitting the Earth in Central Texas this rainy spring. Even on a cloud-free day, that solar energy isn’t all heating the ground. Instead, it's burning off the water that’s soaked into the ground.

“We’ll see how long that lasts," Fitzsimmons says. "The good news is we’ve got rain in the picture.”

But the opposite can happen, too.

Hot In Here

“If it were dry, then the ground would warm up faster and the air would warm up faster,” Fitzsimmons says.

That’s what happened last year: We had a dry hot May and ended up with 52 days of triple-digit heat.

Fitzsimmons says that type of heat can even create “a feedback loop,” where the heat leads to less moisture in the ground, which means less rain, which means more heat.

While you enjoy this relatively cooler spring, it’s important to remember that, overall, things are still heating up.

In fact, Fitzsimmons says, this year may just be more of a return to normal Central Texas temperatures than anything else – though "we’ve got to be really careful with” the word "normal."

In the 20th century, Austin averaged about 13 triple-digit days a year. So far this century, there have been, on average, 38 triple-digit days.

“If we look at the average temperatures since spring 40 years ago, we’re 4 degrees warmer – in just 40 years,” Fitzsimmons says. “That’s a scary and alarming rate.”

Global warming is a big reason why, and turning around the longer warming trends will take more than some spring showers.