the 80s were extremely cold, note how we did not have an August-September low couplet of 45 or colder after the 1980s. in your list it's only 1982, 1986, 1987 with that combo.
Since then the next lowest couplet of August-September is 49 degrees (this year actually.) Besides this year and 2000 every year since 1987 has this couplet combo low of at least 50 or higher.