This Was Austin's Hottest September Ever Recorded. And It Wasn't Even Close.

Sep 30, 2019

Mention the year 2011 to any Austinite who lived here then, and expect to get an earful. It was the hottest year recorded in Austin's history – so hot and so dry that living through it has become a kind of shared trauma for many.

So it might come as a surprise for those who remember 2011 that this year’s September was hotter than the September of that infernal fall. Way hotter.

“It was nuts. It was just crazy,” Spectrum News Chief Meteorologist Burton Fitzsimmons says.

Fitzsimmons says a wet and cool spring had led forecasters to expect a relatively temperate summer this year.

"Then kind of a flash drought set in, and we went nearly two months without rain," he says, "and got our second hottest month in history, which was August.”

And “it just didn’t stop,” he says.

September 2019 was "3 degrees warmer on average from that previous record-holder,” National Weather Service Meteorologist Ethan Williams says. “That’s quite significant.”

By the end of the month, the average temperature was 88 degrees. Compared to the 84.4 degree average of September 2011, that puts this year 3.6 degrees higher than the previous average.

This month also broke the September record for the highest number of triple-digit days, with 19. September 2011, the previous record-holder, had 14 days topping off at 100 degrees or higher.

This month also continued a trend of triple-digit days occurring later and later in the season.

For most of the last century, Fitzsimmons says, Austinites could expect triple-digit days to be over by Aug. 18, but in the last 30 years, 100-degree days have become common up to the end of August. 

"Looking back in the last 10 years, it’s slipped to Sept. 3, and this year will absolutely extend us out even further," he says. “I mean it’s a clear sign of our warming planet, and it's happening now.” 

There may be some relief coming: Forecasters think a mild cold front might move into the area by early next week. But in the long term, hotter summers and falls are part of a new normal as greenhouse gas emissions from fossil fuels continue to warm the Earth’s atmosphere.

This post was updated with the final average temperature.