re: TulaneLSU's Top 10 hottest days and nights in New Orleans history

2. 91.0

New Orleans hit 91 as an average on six days, including four thus far this year:

9/1/2016
7/31/2023
8/7/2023
8/10/2023
8/11/2023
8/12/2003

3. 90.5

New Orleans hit 90.5 as an average on 13 days, including four days thus far this year:

7/14/1932
7/15/1932
7/9/1935
8/26/1938
8/11/2007
8/2/2010
6/26/2016
7/11/2020
7/12/2020
6/29/2023
8/5/2023
8/12/2023
8/14/2023

4. 90.0

New Orleans hit 90.0 as an average on 13 days, including two days thus far this year:

8/19/1909
7/23/1934
6/22/1944
8/1/2010
6/26/2012
7/6/2016
7/7/2016
6/24/2022
8/6/2023
8/9/2023

5. 89.5

New Orleans hit 89.5 as an average on 13 days, including two days thus far this year:

9/8/1931
7/15/1939
7/24/1943
6/20/1944
8/30/2000
6/24/2009
8/10/2015
7/2/2016
9/2/2016
7/24/2021
6/23/2022
6/28/2023
8/13/2023


As interesting as average temperatures are, following Great Grandmother’s lead, I am quite interested in how low a place like New Orleans gets in the summer. It may come as a surprise to many of you, but from 1893 to 1929, Audubon Park averaged more than 24 days with lows in the 60s from June 1 through September 30. 1913 and 1920 even saw it dip into the 40s in September. Most years during those historically hot four months had at least one temperature in the 50s, while 1899 saw 9 days with lows in the 50s! 1899 was quite the chilly year – it was on Valentine’s Day of that year that New Orleans reached its all-time low of 6. Two days later, ice was reported meeting the Gulf at Port Eads. I hope hot chocolate was in ample supply then.

You will notice in the below graph I have designed that there was a substantial dip in the number of days reaching the 60s during summer while the Weather Service had its meter downtown. This likely is a result of being farther away from the Lake, which serves as a cooling source during the day and a warming source at night when most lows occur. It also is likely a product of the urban concrete effect whereby heat absorbs energy from the sun during the day and slowly releases it as heat during the night.

We see the 60s return as the gauge is moved westward to MSY in Kenner. 1965 set the record for most summer nights in the 60s with a remarkable 58 nights. Many of you will remember that year as the summer of Hurricane Betsy, the worst hurricane to hit the city between the Hurricane of 1915 and Hurricane Katrina in 2005. Those who speculate that hot temperatures correlate to an active tropical season, and vice versa, may find this revelation quite surprising.

As recently as 1995, the city had 32 summer nights in the 60s, but a dramatic shift appeared in 1998, coincidentally the same year Juvenile released his album 400 Degreez. Since that summer there have only been 136 June-September nights in the 60s, or an average of 5.2 nights in the 60s, a significant decrease from the recorded average. Moreover, there has been a dramatic uptick in the number of nights that have not dropped below 80.

Between 1893 and 1929, the city saw just nine summer nights that did not drop below 80, an average of 0.19 nights per year. We saw that warm night number increase when the gauge was moved downtown to 50 summer nights in the 80s from the years 1930-1947, for an average of 2.78 nights per summer failing to get into the 70s. MSY, the gauge from 1948-2023 has seen a total of 241 such warm nights, an average of 3.17 ultra hot and muggy nights each.

Most interesting about these warm nights is the rate at which they are occurring now. Beginning in 2005, the year Katrina wiped away so much of our coast, exacerbating an on-going coastal erosion crisis, we have seen 199 nights with lows in the 80s, or an average of 10.5 summer nights each year. 2016 was particularly a bad year with 43 such nights. What once may have been considered an unbreakable record, could fall this year. As of mid-August 2023, we are at 28 nights in the 80s. 9 of the next 10 days are predicted to have lows in the 80s, which would push this year closer and closer to the 2016 record. It will be something to track like we did when McGuire and Sosa battled to reach the Maris record.





Thank you to my friends who suggested I purchase a ruler. It was most useful. Some of you may have missed these graphics from earlier in the week, and they may be of some interest to you:







Sincerely,
TulaneLSU