Now that August is over, the final numbers are in and this climatological summer will end up as the second hottest summer on record in Shreveport with an average temperature of 86.5 degrees.  The summer of 2011 will stay in the record books as the hottest summer with an average of 88.4 degrees.  August of 2023 will go down as the second hottest month ever in Shreveport with an average temperature of 90.5 degrees.  August of 2011 was only slightly hotter with an average temperature of 91.5 degrees.  

Last September I wrote an article that explained the average pace at which temperatures cool down during the fall.  That article considered temperatures from every year dating back to 1874.  This year I’m going to show you that our various firsts and lasts will probably happen a little later than normal

When do we typically see lows in the 50s for the first time?

If you look at data dating back to 1874 in Shreveport, the average date of our first low below 60 is September 17th.  In the autumn months that followed one of the top ten hottest summers the average date of our first night in the 50s is just one day later on September 18th.  The earliest ironically occurred in 2011 on September 6th.  The latest occurred on October 7th back in 1998.  Based on the data from months following the top ten hottest summers, it appears that there is a 70% chance that this year we could dip below 60 on or before September 17th. 

Ready for the chilly 40s?  When could it happen?

The average date of our first night with temperatures below 50 occurs several weeks later on October 8th.  During the ten autumns following one of the hot summers, the average date of reaching that milestone is a few days later on October 11th.  During these ten years, the earliest date of a 40s chill occurred on September 17, 1875.  The latest date fell on November 6th, 1934. There is a 60% chance that we will see our first night in the 40s later than normal this fall.

When could we dip into the 30s for the first time?

If you are ready for some cold, you will have to wait a couple of months.  The average date on which temperatures in Shreveport dipped into the 30s for the first time is October 31st. The average from the ten years that we are considering also falls on Halloween. The earliest date of cold temperatures in the 30s was October 16th, 1943.  The latest date with lows in the 30s was November 23, 1934.   Based on the data from months following the top ten hottest summers, surprisingly it appears that there is a 60% chance that this year we could dip below 40 sooner than Halloween.

When do we experience our first freeze after a very hot summer?

Typically, when we have one of the hottest summers on record we usually see that our first freeze occurs somewhat later than normal.  If you look at the average date of the first freeze for all years dating back to 1874 it occurs on November 20th.  The average date of the first freeze after one of the ten hottest summers is November 25th.  The earliest first freeze of those ten years was October 30th, 1980.  The latest first freeze occurred on December 16th, 1998.  There is a 70% chance that we will have our first freeze this fall on or after November 20th. 

The cold sounds nice but….when does the heat usually end? 

The average date of our last 90-degree day in the years dating back to 1874 is October 2nd.  Our earliest end of 90-degree heat came on August 21, 1879.  The latest 90-degree day on record is October 30, 1937.  During our ten hottest summers the last 90-degree day averages out to be on October 6th.  There is a 70% chance that our last 90-degree day this year will occur after October 2nd.

Obviously, we are sick of triple-digit heat.  In years that experience 100-degree heat, the average last day of that degree of heat is August 17th. During our top ten hottest summers the last day is on average September 3rd.  As of right now, my forecast for next week shows more triple-digits are promising. It’s looking likely that we will meet or beat 100 later than average. In fact, some long-range models do show triple-digits will remain possible through the first half of September. The latest 100-degree day on record in Shreveport is September 29th, 2011.  Let’s hope that we don’t threaten that record this year.  But given that the only summer that was hotter than this summer was 2011, it wouldn’t shock me if we did.  Fingers crossed we don’t!