Whenever you hear any kind of atmospheric scientist reference an average temperature, they’re most likely using the 30 year averages released by the National Oceanic and Atmospheric Administration (NOAA).
The National Centers for Environmental Information (NCEI) is the branch of NOAA that is responsible for releasing new 30 year averages. The official normals are calculated for a uniform 30 year period every 10 years, and consist of annual/seasonal, monthly, daily, and hourly averages and statistics of temperature, precipitation, and other climatological variables from almost 15,000 U.S. weather stations.
This new information is not only required by the World Meteorological Organization (WMO) and the National Weather Service (NWS), but it’s helpful to anyone looking to pack the right clothes for a vacation, farmers to help plant the right crops, and local and national utility companies to plan for seasonal energy use.
The new 30 year averages across the U.S. have indicated that a majority of the country has continued a warming pattern besides portions of the Upper Midwest.
Closer to home, Austin saw a continued increase in temperatures from the 1981-2010 averages to the new normals of 1991-2020.
In addition to the overall increase in temperatures, the average coldest high temperature which occurs in the middle of January was 61 degrees according to the 1981-2010 data. It has now increased to 62 degrees.
The hottest high temperature which occurs in late July and early August also saw an increase from 98 degrees with the 1981-2010 data, to 99 degrees with the 1991-2020 data.
A chart composed by Keith White at the National Weather Service office for Austin/San Antonio compiles even more specific data found below.
Some of the key takeaways from this chart is something we’ve known would be a result of climate change.
The first being what has already been addressed, and that’s that temperatures have risen across Central Texas. Most notably at Austin Mabry and Austin Bergstrom where there have been an increase of about 2 weeks of 90 degree days (line 4).
The second indication of climate change deals with precipitation. Warnings for precipitation extremes (or lack thereof) have been issued in the past. Average Precipitation (line 8) indicates that precipitation has increased for Central Texas. However, the days with at least 0.10″ (line 10) of rain has decreased while the number of days with 1.00″ (line 12) of rain has increased.
What this means is that while overall precipitation has increased. We’re getting fewer and fewer days of rain. But when it does rain, it really does pour.