Key West September Weather

Typical Key West September Weather 1991–2020
Average daily high	88.5 °F
Average daily low	79.0 °F
Average monthly precipitation	7.0 inches

Key West September Weather Records 1948–2023
Highest temperature	95 °F	September 20, 2018
Lowest temperature	69 °F	September 17, 1985
Highest daily low	86 °F	September 4, 2020
Lowest daily high	79 °F	September 29, 1994
Hottest average temperature	2.1 °F above average	2018
Coldest average temperature	-2.2 °F below average	1984
Most daily precipitation	9.4 inches	September 12, 2020
Most monthly precipitation	18.5 inches	1963

Day	Average (°F)		Record (°F)
	High	Low	High	Low
September 1	89.3	79.4	93	73
September 2	89.2	79.4	93	72
September 3	89.2	79.4	95	70
September 4	89.1	79.3	94	70
September 5	89.1	79.3	93	73
September 6	89.0	79.3	92	73
September 7	89.0	79.3	92	73
September 8	88.9	79.3	94	70
September 9	88.9	79.2	92	71
September 10	88.8	79.2	92	74
September 11	88.8	79.2	93	74
September 12	88.7	79.2	92	72
September 13	88.6	79.1	92	71
September 14	88.6	79.1	93	73
September 15	88.5	79.0	93	74
September 16	88.4	79.0	92	72
September 17	88.4	78.9	92	69
September 18	88.3	78.8	92	71
September 19	88.2	78.8	92	71
September 20	88.1	78.8	95	72
September 21	88.0	78.7	93	72
September 22	88.0	78.7	93	73
September 23	87.9	78.7	92	73
September 24	87.8	78.7	92	72
September 25	87.8	78.7	92	74
September 26	87.7	78.6	92	71
September 27	87.6	78.5	91	72
September 28	87.6	78.5	93	73
September 29	87.5	78.4	92	71
September 30	87.4	78.4	92	72