The month in detail
What to expect in September
Autumn marks the end of peak season in Key West. Temperatures drop (84°F) and rain returns (38% of days). Expect rain on 38% of days — a light raincoat in the bag is recommended. Not the best window, but acceptable if dates are constrained. April (9.1/10) is significantly better if possible.
September ranks 11 out of 12 months in Key West. Compared to August: −2°F daytime, 5 pts more rainy days, −0.9h of sun per day.
This month's conditions
What it's like in September
UV index
8 · high
sunscreen and hat advised
Feels like
oppressive heat
24°
Sea
31°C
warm, ideal
Daylight
12.1h of daylight
Air quality
good
AQI 23
Compare
Is September the right month?
The best month in Key West is April (9.1/10), 3.4 pts higher than September.
Book
Plan your trip
Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.
Stay
Hotels & rentals · Key West
Expedia →
Activities
Tours, tickets, experiences
See ↓
Flights
Multi-airline comparator
Kiwi →
🎟️ Activities & tours · Key West
GetYourGuide selection · free cancellation
Practical info
What you need to know before you go
Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a beach trip.
Country · USA
🗣️LanguageEnglish
💶CurrencyUS Dollar ($)
🚗DrivingRight-hand
🛡️Safety ⓘVery safe · 1/5
💰Cost of living ⓘExpensive · 4/5
🌡️ Climate
🌍Climate typeTemperate oceanic
📈Climate trend ⓘStable
🔥Hottest monthJuly · 86°F
❄️Coolest monthJanuary · 73°F
🌧️Rainiest month ⓘSeptember · 38%
🏖️ Beach trip
📅Peak seasonJuin → Sept
🏖️Swell (Sept–Mar) ⓘModérée
Explore
Other destinations in September
If September doesn't convince you for this destination, compare with others.
Location
Where is Key West ?
Global position + regional geographic context.
🌍 World
🔍 Geographic context
USATemperate oceanic climate with a 9.1 → 5.7 gap between best and worst month. 10 years of ERA5 data to choose by project.
24.56°N · 81.78°W
Questions
Frequently asked questions
What is the best time to visit Key West?
April is the best month with 79°F highs, 75°F lows, 10.8h of sunshine and 13.0% rainy days. The months of April & March offer comparable conditions.
How many hours of sunshine does Key West get in April?
Key West averages 10.8 sunshine hours per day in April. It is the sunniest month with a climate score of 8.8/10.
What is the rainiest month in Key West?
September is the most unfavourable month with September has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Key West in April?
In April, overnight lows reach 75°F, while afternoon highs average 79°F.
Is Key West good in winter?
In winter (December-February), Key West scores 8.0/10 on average — Acceptable conditions for cultural visits.. The best month overall remains April with a score of 8.8/10.
When should you avoid Key West?
September is the most difficult month to visit Key West, with September has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.
Can you swim in Key West in September?
In September, the sea averages 88°F in Key West: warm, ideal. Ideal conditions for swimming and snorkeling.
Do you need sun protection in Key West in September?
The average UV index reaches 8 in September in Key West (high), with about 12.1h of daylight. Sunscreen and hat advised.