AUSTIN, Texas — When tracking record-breaking heat, most of the national headlines around the country are focused on high temperatures each afternoon.
But what if we were to take a look at low temperatures?
There is scientific evidence that suggests that nighttime heat is increasing at an exponential rate for much of the United States. A climate report from Climate Central in 2022 claims that summer minimum temperatures have warmed nearly twice as fast as summer maximum temperatures.
It is effecting the southern half of the United States at a greater magnitude. Below is the most recent CSI (Climate Shift Index) for Austin in 2024.
According to the scale, this means the effects of climate change will have made it three-times more likely to impact low temperatures today. In large metropolises like Dallas and Houston, its four-times more likely.
Looking at our own nighttime temperatures in Austin, normal low temperatures for the summer months hover around 72 degrees. So staying at 80 degrees overnight can be considered a very warm evening.
Over 20-year periods, since records began at Camp Mabry in 1897, the number of nights that stayed at 80 degrees or above has skyrocketed. From 2002-2022, the study noted 11 more days than counted in any prior period.
And in the first two years of our next 20-year period, we are already up to 19 nights at or above 80 degrees.
So far in 2024, 13 of 24 record reports the National Weather Service has published for Camp Mabry have either tied or set a record high minimum temperatures.
At Austin's airport, five out of 15 record event reports have been due to record high minimum temperatures in 2024.
Some of this warming can be attributed to the rapid growth of Austin, which has subsequently made the city into an "urban heat island," meaning city surfaces can reflect and absorb heat, thus raising the temperature by a few degrees, especially on warm and clear days.
However, it's important to note that many places across Texas and the U.S. are recording this rise in nighttime heat, even in places that do not have enough infrastructure to experience the heat island phenomenon.
An example is San Angelo, TX. Here is a least of low temperatures at or above 80 degrees since their data intake began.
- 1907-1927 0 days
- 1928-1948 2 days
- 1949-1969 13 days
- 1970-1990 5 days
- 1991-2011 18 days
- 2012-present 40 days
