AUSTIN (KXAN) — It was difficult to tell by the daily high temperatures in July, but the fact remains that Austin is susceptible to extreme heat streaks.
Current extreme heat streaks are a period of three or more consecutive days where the maximum temperature reflects the hottest 10% of the daily maximum temperature recorded in a location from 1991 to 2020. This 30-year time period provides the last set of daily normal high temperatures.
Climate Central, a KXAN media partner, did an analysis of the increased frequency of extreme heat streaks in 247 cities across the United States, including cities in Alaska and Hawaii.
The data showed that 198 (80%) of those cities, including Austin, saw more extreme heat streaks than back in the 70s. The average number of those heat streaks increased by at least two each year.
For Austin, the heat streak is defined as three (or more) consecutive days with maximum temperatures above the 90th percentile. These extreme heat streaks reflect the hottest 10% of the daily maximum temperature recorded at the Austin reporting site between 1991 and 2020.
This area is no stranger to such streaks. For us, however, we tend to think of these streaks as when the daily high is 100° or higher. Let’s go back to 2023 to find one such heat streak stretching for 45 days between July 8 and August 21, where the high temperature exceeded 100°. Now, that’s a heat streak.
According to the data gathered, Austin saw an increase of 5 heat streaks between 2010 and 2019. That number came down in the five years from 2020 to last year. But in a warming climate, and with 4.5 years to go in this decade, it stands to reason that as heat-trapping pollution continues to warm the planet, the number of extreme heat streaks in this decade could go up.
There are no positives to heat streaks. These streaks that can last for days make it more than just uncomfortable. It can worsen the air quality. How? Hot air hastens the formation of ground-level ozone. Increasing wildfires release harmful particulate matter into the air.
Heat streaks can lead to an increase in the risk of heat-related illness. We have discussed this many times. And, they can strain the power grid, knocking out the a/c when we need it the most.
So, it’s not just Austin and Texas that feel the effects of these streaks. Cities in the Ohio Valley, the northeast, the southeast, and the southwest are seeing longer heat streaks.
July has seen one three-day heat streak with highs of 98° on the 22nd and 23rd, and the month’s first 100° high on the 24th. That streak, such as it was, ended with a high of 90° on the 25th.
We’ll be following this for the rest of this month and especially in August, the hottest month of the year.