What is causing the heatwave?

A phenomenon characterized by cooling waters across the central and eastern pacific oceans, La Niña tends to cause cooler and wetter conditions in the northern U.S. but warmer and drier conditions across Central Texas. We would typically be on our way out of La Niña at this time of year, according to White, but the heat can be turned around with a little rain.

White explained that the sun is able to heat dry ground—due to the drought and La Niña—more efficiently than wet ground. West Austinites might be feeling more of the heat, as the drought has been worse west of town.

Austin is entering its rainy season, which tends to fall between May and October. The last 30 days have seen about 2-4 inches of rain, which is just a touch below average, but White said the end of May is looking rainy, which could quell the heat.

“There will be some dependency on if we're able to pick up some more beneficial rains here,” White said. “While at least over the course of the next week it looks likely to remain dry, there may be some rain chances returning toward the end of May.”

Does a record-breaking May mean a record-breaking summer?

Not necessarily, though in part due to climate change, all of the top five hottest summers have been recorded since 2008 with the hottest to date in 2011. Meanwhile, 2021 was only the 38th hottest summer on record.

White said that means climate variability is superimposed against climate change, meaning temperatures are gradually rising, but the amount of rain we receive could make a huge difference.

While 2011 saw more than 90 100-degree days, 2021 only saw 12 100-degree days.

“As our climate warms, the risk of excessive heat will increase because you're taking the average temperature and moving it up,” White said.

How to stay safe and cool

With rising temperatures, there is always a risk of heat-related illness. In fact, White said last weekend there were 29 heat-related illness calls to Austin EMS.

The best way to avoid getting sick in the hot Texas summer is to wear light clothing, drink lots of water, take breaks in air-conditioned areas and familiarize yourself with symptoms of hyperthermia.

And prepare yourself for the first half of August, which is traditionally the hottest time of year.