Ketchum September Weather

Averages and records for weather in Ketchum, Idaho in the month of September.
Typical Ketchum September Weather
1991–2020
Average daily high 70.0 °F
Average daily low 35.6 °F
Average monthly precipitation 0.7 inches
Average monthly snow 0.0 inches
Ketchum September Weather Records
1937–2023
Highest temperature 93 °F September 1, 1955
Lowest temperature 11 °F September 30, 1954
Highest daily low 55 °F September 16, 2014
Lowest daily high 39 °F September 17, 1965
Hottest average temperature 4.4 °F
above average
1998
Coldest average temperature -8.0 °F
below average
1941
Most daily precipitation 1.6 inches September 6, 1978
Most monthly precipitation 4.7 inches 1985
Most daily snow 3.0 inches September 18, 1978
Most monthly snow 3.5 inches 1954
Note: Daily averages are a moving average which includes 14 days before and after
Day Average (°F) Record (°F)
High Low High Low
September 1 75.3 39.3 93 21
September 2 75.0 39.1 92 24
September 3 74.6 38.9 92 16
September 4 74.1 38.7 90 15
September 5 73.6 38.4 90 21
September 6 73.2 38.1 90 18
September 7 72.8 37.8 92 20
September 8 72.4 37.5 90 20
September 9 72.0 37.3 88 17
September 10 71.6 37.1 86 13
September 11 71.3 36.8 87 22
September 12 70.9 36.5 86 19
September 13 70.5 36.3 86 16
September 14 70.2 36.0 86 18
September 15 69.9 35.9 87 13
September 16 69.7 35.6 84 16
September 17 69.4 35.4 85 13
September 18 69.1 35.2 86 12
September 19 68.6 34.9 85 13
September 20 68.0 34.5 83 12
September 21 67.5 34.2 84 17
September 22 67.0 34.0 85 12
September 23 66.5 33.7 83 16
September 24 66.1 33.4 84 14
September 25 65.7 33.2 84 15
September 26 65.2 32.8 83 17
September 27 64.8 32.5 84 17
September 28 64.3 32.2 84 14
September 29 63.8 31.8 84 13
September 30 63.4 31.5 82 11
Weather Station Details
Years Station Coordinates
1973–2023 Ketchum location
1937–1972 Sun Valley location