Josh Eachus is a meteorologist at WBRZ News 2 in Baton Rouge, Louisiana.

Abnormal Autumn: Fall Freezes Are Getting Later in South Louisiana

  • Nov 6, 2015

Fall fanatics along the Gulf Coast have been asking, “shouldn’t it be cooler by now?”

Meanwhile, warm weather lovers have nothing to complain about. Since Sept. 1, temperatures have run 2.9°F above average in Baton Rouge and 2.8°F warmer than normal in New Orleans.

A ridge dominating the eastern U.S. has kept numbers up through November as well with both of southeast Louisiana’s big cities more than 5.5°F warmer than usual.

CONUS weather

Ridge in the East, trough in the West on November 3.

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The numbers are fairly remarkable given the gloomy, cloudy and rainy weather that has played out across Louisiana since the beginning of the month.   

Surely, it has been a victory for fans of flip-flops in the fall — especially when considering the previous two editions of the eleventh month. Both 2013 and 2014 in particular saw unusually cold Novembers in Louisiana.

In 2014, the Capital City of Louisiana was a remarkable 5.8°F below average for the month with five freezes and four mornings in the 20s. It was extra scary for Southerners when a Halloween cold front helped November lead off with three mornings in the 30s. Warmer farther south? Hardly. The Crescent City was 4.7°F cooler than usual with one freeze and six mornings in the 30s.

November average temperatures

November average temperatures compared to 2014 for Baton Rouge and New Orleans.

Laughable by northern cold season standards, let’s put these numbers into perspective. Since 1970, in Baton Rouge November highs average around 71°F and lows average about 48°F. In New Orleans the numbers are 72°F and 52°F respectively. Of course, it is much warmer in the beginning of the month and cooler at the end. Traditionally the first freeze occurs around Nov. 28 in Baton Rouge and Dec. 12 in New Orleans.

Both cities tend to register a low temperature in the 30s within the first 10 days of the month, but the latest forecast models show no sign of getting close to the 30s through the third week.

GEFS Ensemble Temperatures for New Orleans 11/5 – 11/20

GEFS Ensemble forecast temperatures for New Orleans through Nov. 20.

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Fluctuations from cooler to warmer than average one year to the next are hardly out of the ordinary. However, gradual changes in the weather pattern over multiple decades are more noteworthy.

If trends of the last 35 years continue, a November like 2015, and not 2014, will become the norm. At least in Baton Rouge and New Orleans, there is a gradual upward trend of average temperatures in November.

The number is a bit more pronounced for Baton Rounge, which is farther inland. In New Orleans, marine influences from the Gulf of Mexico and Lake Pontchartrain have greater moderating effects on short- and long-term temperature trends.

Cold weather crusaders looking for the cooler, crisp temperatures will be even more upset by this next trend.

Let us reevaluate some of the freeze statistics in greater detail. From 1951-1980, the average first freeze occurred on Nov. 21 in Baton Rouge and Dec. 5 in New Orleans. From 1981-2010, the average first freeze fell on Nov. 28 in Baton Rouge and Dec. 18 in New Orleans.

First freeze Baton Rouge

Date of first freeze in Baton Rouge.

First freeze New Orleans

Date of first freeze in New Orleans.

Is the cool season crumbling along the Gulf Coast? Breaking the data set from 1951 into two 30-year intervals shows that the indeed, the time from first freeze to last freeze is also shrinking.

From 1951-1980, Baton Rouge averaged 93 days from the first to the final freeze. From 1981-2010, that mark dropped to 88 days. In New Orleans the earlier period averaged 76 days from first to last freeze while the latter of the two typically lasted only 49 days.

So fall fanatics along the Gulf Coast, yes, it should be cooler by now. And this will give warm weather lovers something to complain about — a longer mosquito season!