A hot summer even by Alabama standards: where 2016 falls in the record books

There are numerous ways to measure how hot the summer has been; on WHNT News 19 we have used two different methods to describe it: high temperatures only and the average daily temperatures (high and low).  Huntsville only had one 100-degree day, but we have had 48 days above 95ºF and 93 days above 90ºF.  Both of those numbers are well above the norm over the past 50 years.

Dr. John Christy is Alabama’s State Climatologist, and he has a very good analysis here showing why the measurement using the daily average is not always the best way to go.  His summer climate report is below:

Average of daily high temperatures via Dr. John Christy (Alabama's four largest metro areas)

Average of daily high temperatures via Dr. John Christy (Alabama’s four largest metro areas)

Alabama summer warmer than usual

HUNTSVILLE, Ala. (Sept. 13, 2016) — It probably comes as no surprise, but summer days in 2016 were warmer than normal over most of Alabama.

Using a dataset that looks at daily high temperatures from 119 weather stations within a 50-mile radius around each of the state’s four largest cities going back more than 130 years, State Climatologist John Christy found that this summer was warmer than normal for Birmingham, Huntsville, Mobile and Montgomery.

It was the 13th warmest summer on record for Montgomery and the region around it, with average daily highs of 95.31° Fahrenheit for June, July and August. The average summer high for Montgomery is 92.89°, while the warmest summer on record was in 1902, when the average summer high in Montgomery was 97.86°.

The four cities together had their 24th warmest summer in 133 years, with an unweighted average daily high temperature of 92.63°. The unweighted 133-summer average for the four cities and their surrounding regions is 90.96°. The warmest Alabama summer in this dataset was 1954, when the average daily high temperature was 95.72°.

It was the 17th warmest summer in the Huntsville area, with an average daily high of 92.61°, compared to a seasonal average of 90.07°. It was the 35th warmest summer in Birmingham (91.36° compared to a summer norm of 90.12°), and the 38th warmest summer in Mobile (91.45° with a summer average of 90.76°).

In general, Alabama’s summers have been cooling, especially since 1954. For the four major city’s and their surrounding areas, the long-term cooling rate from 1883 to today is 0.09° per decade.

This dataset uses only daily high temperatures to create a climate record that avoids the climate shifts in nighttime low temperatures caused by local human effects, such as deforestation, urban growth, paving and irrigation.