Temperature for August
In Watertown, SD during August the average high temperature is 81.7°F. The hottest day on record was August 17, 1988 when the temperature hit 100.9°F.

In Watertown, SD during August the average high temperature is 81.7°F. The hottest day on record was August 17, 1988 when the temperature hit 100.9°F.
In August the average monthly rainfall in Watertown, SD is 2.11 inches with rain usually falling on between 8 and 9 days. 1949 was the driest August with only 0.00 inches of rain falling, and 1979 was the wettest August with 5.25 inches of rain. The wettest single day in August was 10 August 1994 when 3.39 inches of rain fell.
There are thunderstorms on between 4 and 5 days in August.