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Castle Rock September Weather

Averages and records for weather in Castle Rock, Colorado in the month of September.

Typical Castle Rock September Weather 1991–2020
Average daily high	77.2 °F
Average daily low	46.1 °F
Average monthly precipitation	1.4 inches
Average monthly snow	0.5 inches
Daily chance of precipitation	19.3%
Daily chance of snow	0.84%

Castle Rock September Weather Records 1893–2024
Highest temperature	101 °F	September 12, 2021
Lowest temperature	11 °F	September 28, 1984
Highest daily low	71 °F	September 1, 1905
Lowest daily high	35 °F	September 29, 1999
Hottest average high temperature	88.6 °F	2021
Coldest average high temperature	68.5 °F	1912
Most daily precipitation	2.8 inches	September 15, 2013
Most monthly precipitation	6.5 inches	2013
Most daily snow	10.5 inches	September 17, 1971
Most monthly snow	11.5 inches	1971

Note: Daily averages are a moving average which includes 14 days before and after

Day	Average (°F)		Record (°F)
Day	High	Low	High	Low
September 1	81.4	50.9	97	38
September 2	81.2	50.7	96	34
September 3	81.0	50.5	98	31
September 4	80.9	50.2	93	35
September 5	80.7	49.9	96	36
September 6	80.4	49.6	99	35
September 7	80.1	49.3	96	34
September 8	79.7	49.0	96	32
September 9	79.3	48.6	95	29
September 10	79.0	48.2	96	29
September 11	78.5	47.8	99	28
September 12	78.2	47.4	101	26
September 13	77.9	47.0	92	29
September 14	77.6	46.6	91	25
September 15	77.3	46.2	91	21
September 16	77.0	45.9	94	26
September 17	76.7	45.6	96	23
September 18	76.4	45.2	91	22
September 19	76.0	44.8	97	15
September 20	75.6	44.5	92	20
September 21	75.2	44.0	90	22
September 22	74.7	43.7	89	23
September 23	74.4	43.3	87	27
September 24	74.1	42.9	90	23
September 25	73.7	42.5	91	17
September 26	73.2	42.0	93	20
September 27	72.7	41.6	91	13
September 28	72.4	41.3	91	11
September 29	72.1	40.9	87	23
September 30	71.7	40.4	87	20

Weather Station Details

Years	Station	Coordinates
1893–2024	Castle Rock	location