A Trend Towards Fewer Cool Summer Nights (Lows in 50s)
In the decades between 1910-1980 the average number of days with morning lows in the 50s during the summer (mid-June thru mid-Sept) was twelve. Since then the number has fallen sharply, and in the current decade (thru 2019) the average has fallen to 3.4 days. In 2016, for the first time, there were no lows in the 50s during the summer (1966 had one and six summers have had two such days, including 2015). The greatest number occurred in 1940 when there were 33 days. In recent years the most 50-degree readings was 19 in 1986, and 13 in 2007 (which is the only summer in the past 21 years to have more than 10). Since 1991 twelve summers have had no lows in the 50s in July or August (including 2014 thru 2019). There were ten such summers in the years between 1910 and 1990.
| AVERAGE NUMBER OF 50-DEGREE LOWS | ||
| EACH SUMMER BY DECADE | ||
| 2010-2019 | 3.4 | |
| 2000-2009 | 6.4 | |
| 1990-1999 | 8.2 | |
| 1980-1989 | 8.9 | |
| 1970-1979 | 10.8 | |
| 1960-1969 | 12.6 | |
| 1950-1959 | 11.3 | |
| 1940-1949 | 12.6 | |
| 1930-1939 | 10.0 | |
| 1920-1929 | 16.3 | |
| 1910-1919 | 15.1 | |
| FEWEST/MOST COOL SUMMER NIGHTS | ||||
| (June 16 - Sept 15) | ||||
| Fewest | Most | |||
| 1966 | 1 | 1940 | 33 | |
| 2015 | 2 | 1963 | 27 | |
| 2011 | 2 | 1927 | 25 | |
| 1996 | 2 | 1926 | 24 | |
| 1993 | 2 | 1914 | 24 | |
| 1983 | 2 | 1946 | 23 | |
| 1931 | 2 | 1918 | 22 | |
| 2019 | 3 | 1924 | 21 | |
| 2013 | 3 | 1962 | 20 | |
| 2005 | 3 | 1986 | 19 | |
| 1981 | 3 | 1965 | 19 | |
| 1971 | 3 | 1915 | 19 | |
| 1961 | 3 | |||
| Average = 11 | ||||
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