September 2016 was characterized by seasonable temperatures at both the beginning and end of the month and unseasonably warm conditions during the days in between (Sept. 6-23); temperatures during this summery two-and-a-half week period were nearly seven degrees above average. As a whole the month was 3.8 degrees warmer than average, tying Sept. 1983 and 1884 as the tenth warmest on record (this followed the third hottest August).
Three days had highs in the 90s and seven had mean temperatures that were ten degrees or more above average (one of which was the first day of autumn). There were just five days with below average temperatures. The most below average was 9/30, with a high of 59/56 (it was the high that was below average, by 11 degrees) - this was the first day in September with a high in the 50s in fifteen years.
OTHER SEPTEMBER HIGHLIGHTS
- The high on Labor Day was 84°, which was the same as Fourth of July and very close to Memorial Day's high (82°). This was just the third time since 1970 that that three summer holidays had very similar highs. But whereas Memorial Day's high was seven degrees above average and Labor Day's five above, 4th of July's was at the seasonal average.
- On Sept 11 the heat index was 101°.
- The three 90-degree days in September brought the year's total to 22, five above average and the most since 2010. The 91-degree reading on 9/14 was the latest high in the 90s since 1995 (when it occurred on 9/15).
- Although September's rainfall was below average, more fell than in August (2.79" vs. 1.97"). There were no storms that produced an inch or more of rain but three had a half-inch or more (on 9/14, 0.56" poured down in an hour during a late afternoon thunderstorm). The rainiest day was 9/19 when 0.68" fell. Since March, all but one month (July, with 7.02") has had below average rainfall, resulting in a deficit of nearly 10 inches in these seven months (20.91" vs. 30.78") .