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Key West in September: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Key West in September is climatically mixed. The average daily high is around 29 °C, and the sea is about 30 °C. With about 24 rainy days it is very wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
54/100 · #11
Warmth
#3
Dryness
#10
Sun
#7
Sea warmth
#3
Published best categories: none
Key West · SeptemberPhoto: Ebyabe · CC BY-SA 3.0Climate facts
- Average high
- 29 °C
- Average low
- 29 °C
- Sea
- 30 °C
- Rainy days (est.)
- 24 rainy days (est.)
- Sun (est.)
- 7 h/day
- Humidity
- 77 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 30 | 29 | 26 | 188 | 7.6 | 75 | 3.8 | 30 | 52 |
| September (selected) | 29 | 29 | 24 | 198 | 6.7 | 77 | 4.0 | 30 | 54 |
| October | 28 | 27 | 17 | 130 | 5.9 | 77 | 5.1 | 28 | 65 |
How do the previous and next months compare?
Baseline: September (54/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | -2 | +0.5 °C | +0.5 °C | +1.8 | -10.2 mm | +0.9 h | -1.3 % | -0.2 m/s | +0.5 °C |
| October | +11 | -1.4 °C | -1.5 °C | -7.2 | -68.1 mm | -0.8 h | +0.2 % | +1.1 m/s | -1.4 °C |
All twelve months in context
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Useful next decisions
Frequently asked questions
How warm is Key West in September?
The average daily high is around 29 °C, with an average daily low of about 29 °C.
Can you swim in Key West in September?
The sea is about 30 °C (very warm).
Does it rain a lot in Key West in September?
The curated estimate is about 24 rainy days per month, not a directly measured long-term average. Total precipitation averages around 198 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Key West?
By the climate score, February, March, April and December are the strongest months for Key West. For a beach trip: February, March, April and November. September is not among them.