The hot summer so far

It is interesting how so far in 2010, we have had a historically long cold snap, but the lowest temperature was only 12 degrees, and now we have had a long heat wave, but the highest temperature has been 101.  Not that 12 is not cold and 101 is not hot, but most severe cold waves see nights below 10, and most heat waves see highs of 103 or 104, at least.  For more on the January cold wave, see Cold wave.

Taking a look at this summer’s heat wave so far statisically, a caveat is necessary. Taking a look at 60-day moving averages, this summer doesn’t even make the top 5 hottest in average daytime high temperature, but it is number 1 in warmest average morning low (74.4 degrees).  Also note that 3 of the top 5 warmest morning low periods have occurred since 2005.  That is likely, in part, due to the urban heat island around the airport at night (it is sometimes 5 degrees warmer at the airport than in Pinson, Sylvan Springs, or McCalla).  So, the overall average temperature gets artificially inflated slightly.  However, the daytime temperatures are affected little by the urban effect, since mixing occurs. 

Just like with the cold wave in January, it has not been the extremity of the heat, but the duration.  Including today, we have already had 32 days with high temperatures at or above 95, putting us in 15th place in 110 years.  We only need 7 more days above 95 to make it into the top 10 in that category.  We have had 6 days with highs above 100 degrees.  However, as you can tell from the chart at the top of this post, most days have had above normal temperatures.  65 of the 69 days so far this summer (since June 1) have been hotter than normal!  The last time the low was in the 60s was July 5, and the last time the high was in the 80s was July 4.  Over the past 30 days, it’s been at least 95 on 25 days.

Also, we’ve had a lot of hot days, but the temperatures have generally stayed below 100, due to the soil moisture.  This has made it feel a lot hotter, and has kept nighttime temperatures higher.

Overall, our average temperature this summer is 83.7.  If that continues, this will be the warmest summer ever in BHM.  We’ll see.

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