July 21 is generally a great time to visit Key West. While there is a slight chance of rain (27%), showers are usually brief. Expect comfortable 29°C weather. You'll enjoy Key West with reasonable crowd levels and competitive accommodation options.
View the full calendar
Essential Travel Info for Key West
Currency
USD
$ United States dollar
Language
English
Driving
Right side
Safety
Moderate Safety
GPI: 2.44
Key West Weather Forecast for July 21
"Warm & Sunny. Expect average highs of 29.3°C. 27% chance of rain."
What to Wear in Key West in July
Based on historical data for July 21, Key West typically experiences temperatures between 27.6°C and 29.3°C. We recommend packing t-shirt, light clothing to stay comfortable. With a 27% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Key West
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
29.3°C
Daytime Peak
Average Low
27.6°C
Nighttime Low
Feels Like
34.9°C
🔥 Heat index effect
Rain Chance
27%
Avg 1.3mm if it rains
Cloud Cover
56%
Light drizzle
Pressure
1017 hPa
Low volatility
Key West Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
~ Weather is generally predictable, but pack for minor variations. A light backup layer is recommended.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30+ required, seek shade
05:00 - 10:00
16:00 - 19:00
Type I-II
🔴 13 min to burn
Type III-IV
🟡 20 min to burn
Type V-VI
🟢 33 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
24.8°C
Humid/Sticky
Heat Index
34.9°C
Feels hotter
😕 Best outdoor time:
Morning hours (before 11 AM)
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
✅ Excellent Swimming Conditions
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in United States
Flight Traffic
Moderate
46/100 pressure index
Health Advisory
Healthy
Routine only • View Details →
Landing Slots
~18
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Key West
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:51
☀️ Noon
12:34
🌇 Sunset
19:17
⏱️ Daylight
13h 26m
Wind Speed
22.8 km/h
Moderate wind
Sunshine
11.9 hrs
Direct Sun (Cloud-free)
Humidity
77%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Key West
Smart Flight Estimator
Airport-to-Airport Logistics
unlock smart flight estimates
Add your home location in settings to see airport details.
Travel Health & Safety in Key West
Travel Comfort Index
Real-time tourism conditions
Weather Quality
⛅ Good
Tourist Crowds
🔴 Very Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Stable conditions. Low risk of headaches.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Zero seismic activity detected in 30 years.
Atlantic Hurricane Risk
Season: Jun - Nov
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Key West on July 21 averages 29.3°C with a 27% precipitation probability. Wedding/Outdoor Event Score: 90/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Key West Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
July 19
29.3°C • 21% rain
Score
92
July 16
29.2°C • 28% rain
Score
91
July 17
29.3°C • 23% rain
Score
91
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (July 21) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Key West Worth Visiting on July 21?
Planning a trip to Key West on July 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 29.3°C with a 27% historical precipitation risk.
✈️ Travel Logistics: Approximately 18 landing slots available daily during this period, indicating manageable crowd levels.
🌊 Coastal Conditions: Water temperature averages 31°C (hot soup). Wave conditions are generally fun waves with heights around 0.75m.
📊 Historical Extremes: The hottest July 21 recorded in the last 30 years saw temperatures hit 30.4°C in 2023, while the coldest dropped to 25.6°C in 2020.