Temperatures in Washington in December were below normal, but overall for 2016 they were above normal. According to the National Weather Service, the average temperature last month was 24 degrees, below the normal 24.9 degrees. For 2016, the average temperature was 52.5 degrees, above the normal 49.4 degrees. Usually for the year the average high temperature in Washington is 60.6 degrees, however last year it was 63 degrees. Total precipitation for Washington in 2016 was below normal at 30.33 inches; normally it is about 36.5 inches.