AUSTIN (KXAN) — Austin is in the midst of the longest continuous stretch of 100º heat in 125 years of record keeping at Austin’s Camp Mabry. Determining when the triple digit streak will end will be the challenge of your favorite meteorologists over the course of the next week or two.

Historical end to triple digits in Austin

We do know that time is on our side. Weather averages are taken over a 30-year period from 1991-2020. During that period our average FINAL triple digit day of the year was August 30.

Average last 100º day in Austin
Average last 100º day in Austin

Of course, we’ve had years when the triple digits continued much later into the year. In fact, on two occasions we had triple digits last into October!

Latest triple digit days in Austin
Latest triple digit days in Austin

Over the last few years we’ve seen triple digits ending later than normal. Except for last year (2022), when triple digits ended earlier than normal, we’ve seen triple digits in September 4 out of the last 5 years.

Recent final 100º days in Austin
Recent final 100º days in Austin

When will we end our current triple digit streak?

Figuring out when our luck will change is difficult, but for the last few days our medium-range forecasting models have suggested some temperature relief may arrive after the middle of August.

The ECMWF (European Computer Model) Ensemble temperature forecast for Austin’s Camp Mabry finally brings high temperatures down below 100º by Monday August 21.

EURO Ensemble Temperatures for Austin (Weatherbell)
EURO Ensemble Temperatures for Austin (Weatherbell)

That still means another two weeks of triple digit heat.

Better still is the GFS (Global Forecasting System – American Model) that brings highs down below 100º even earlier. The GFS brings triple digit relief by August 17 and keeps us under 100º for at least a few days.

GFS (American Model) Ensemble Temperatures for Austin (Weatherbell)
GFS (American Model) Ensemble Temperatures for Austin (Weatherbell)

Yes…but

We’ve seen signs of hope before that have turned hotter and drier when the forecasted relief got closer. However, a mid-month change isn’t just a blip in our models. They’ve been relatively consistently pointing toward some change for the last few days.

Cautious optimism may be key here. Of course, we’ll keep you informed of any adjustments to expectations…for better or worse!