Another record broken: September 2023 measures in as the hottest on record in San Antonio

New record comes after the hottest summer ever recorded in San Antonio earlier this year

September 2023 measures in as the hottest on record in San Antonio

After a record-breaking summer in San Antonio, 2023 goes down in the books yet again with this September measuring in as the hottest September on record in the Alamo City.

Key points

  • September 2023 now snags the top spot for hottest September on record, with an average temperature of 87.0 degrees in San Antonio.
  • The average temperature takes into account the morning low and afternoon high temperature of each day, averaged out over the 30 day period.
  • The previous hottest September was in 2019 with an average monthly temperature of 85.8 degrees.
  • Records date back to 1885, 138 years ago.
  • This comes after August 2023 measured in as the hottest month ever recorded in San Antonio and summer 2023 rang in as the hottest summer on record.

Breaking down the numbers

Hot afternoon highs and warm morning lows throughout the month of September contributed to what has seemed like a never-ending summer stretch.

  • The average daily high temperature for September 2023 was 98.2 degrees, 8.1 degrees hotter than the average high of 90.1 degrees.
  • The average daily low temperature for September 2023 was 75.8 degrees, 6.2 degrees warmer than the average low of 69.6 degrees.
  • Averaging the highs and lows together over the entire 30 day period brings us to the hottest average temperature in September on record for San Antonio: 87.0 degrees in 2023.
Each day was warmer-than-average in San Antonio throughout the month of September in 2023.

September 2023 now moves into first place, sending 2019 into the second top spot with an average monthly temperature of 85.8 degrees. September 1911 now comes in third, followed by 2005 and 1986.

In addition, with each day ringing in well above the 90 degree mark throughout the month, September as a whole tacked on significantly to the longest consecutive streak of 90 degree+ days on record in San Antonio, with the current streak through September 30 ringing in at 115 days and counting.

So that brings us to the obvious question:

Is there any relief in sight?

Here’s some good news: confidence is increasing regarding a pattern change the first week of October!

While the first half of the week will still consist of temperatures in the 90s and just isolated rain, the first cool front of the season is looking more likely to arrive by Wednesday night and Thursday morning.

Higher rain chances are forecasted to accompany the front, followed by highs in the 80s and lower humidity for the start of next weekend. It’s not time to break out the coats and scarves just yet, but it’s a start!

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About the Author:

Meteorologist Mia Montgomery joined the KSAT Weather Authority Team in September 2022. As a Floresville native, Mia grew up in the San Antonio area and always knew that she wanted to return home. She previously worked as a meteorologist at KBTX in Bryan-College Station and is a fourth-generation Aggie.