Key Largo Weather in September
Average highs run from 89°F on September 1 to 87°F on September 30, and lows from 78°F to 78°F. Normal precipitation for the month is 7.98 in over about 13 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 88°F
- Average low
- 78°F
- Precipitation
- 7.98 in
- Record high
- 97°FSep 24, 2021
- Record low
- 65°FSep 14, 2019
- Chance of a freeze
- 0%
- Days of 90°F or more
- 8.3
- Daylight
- 12 h 37 min to 11 h 56 min
- Cloud cover
- 65%
- Humidity
- 77%
- Dew point
- 75°F
- Wind
- 9.6 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 89°F | 78°F | 93°F 2023 | 73°F 2021 | 43% |
| Sep 2 | 89°F | 78°F | 93°F 2020 | 74°F 2007 | 43% |
| Sep 3 | 89°F | 78°F | 92°F 2020 | 75°F 2009 | 43% |
| Sep 4 | 89°F | 78°F | 92°F 2020 | 75°F 2006 | 44% |
| Sep 5 | 89°F | 78°F | 92°F 2020 | 72°F 2006 | 44% |
| Sep 6 | 89°F | 78°F | 93°F 2026 | 73°F 2006 | 44% |
| Sep 7 | 88°F | 78°F | 92°F 2019 | 73°F 2008 | 44% |
| Sep 8 | 88°F | 78°F | 92°F 2022 | 74°F 2013 | 44% |
| Sep 9 | 88°F | 78°F | 92°F 2019 | 72°F 2007 | 44% |
| Sep 10 | 88°F | 78°F | 93°F 2024 | 73°F 2007 | 45% |
| Sep 11 | 88°F | 78°F | 92°F 2012 | 73°F 2007 | 45% |
| Sep 12 | 88°F | 78°F | 93°F 2022 | 73°F 2007 | 45% |
| Sep 13 | 88°F | 78°F | 92°F 2022 | 73°F 2014 | 45% |
| Sep 14 | 88°F | 78°F | 92°F 2022 | 65°F 2019 | 45% |
| Sep 15 | 88°F | 78°F | 93°F 2024 | 73°F 2011 | 45% |
| Sep 16 | 88°F | 78°F | 92°F 2024 | 74°F 2006 | 45% |
| Sep 17 | 88°F | 78°F | 93°F 2019 | 74°F 2006 | 45% |
| Sep 18 | 88°F | 78°F | 92°F 2019 | 74°F 2004 | 45% |
| Sep 19 | 88°F | 78°F | 91°F 2020 | 73°F 2007 | 45% |
| Sep 20 | 88°F | 78°F | 91°F 2012 | 73°F 2006 | 45% |
| Sep 21 | 87°F | 78°F | 91°F 2020 | 72°F 2004 | 45% |
| Sep 22 | 87°F | 78°F | 91°F 2022 | 74°F 2014 | 45% |
| Sep 23 | 87°F | 78°F | 92°F 2022 | 72°F 2014 | 45% |
| Sep 24 | 87°F | 78°F | 97°F 2021 | 71°F 2007 | 45% |
| Sep 25 | 87°F | 78°F | 90°F 2011 | 71°F 2007 | 44% |
| Sep 26 | 87°F | 78°F | 92°F 2022 | 70°F 2007 | 44% |
| Sep 27 | 87°F | 78°F | 92°F 2020 | 71°F 2008 | 44% |
| Sep 28 | 87°F | 78°F | 92°F 2013 | 71°F 2016 | 44% |
| Sep 29 | 87°F | 78°F | 92°F 2024 | 70°F 2019 | 44% |
| Sep 30 | 87°F | 78°F | 91°F 2023 | 69°F 2022 | 44% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 7:03 AM, sunset 7:40 PM
- September 30
- sunrise 7:14 AM, sunset 7:10 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00088841 (Tavernier), public domain. Records: NOAA GHCN-Daily, station USC00084412, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.