Keystone, United States experiences average highs of 26°C (79°F) and lows of 20°C (68°F) throughout the year. Rainfall is moderate, averaging about 12 rainy days per month. Sunshine is abundant, averaging about 10 hours per day. High humidity combined with warm temperatures produces a tropical feel year-round. Average highs have stayed broadly stable across the available records.
Keystone, United States Weather & Climate 2026
Monthly climate averages for Keystone, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: May–Oct At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
6.8/10
Best: February, March, April, November, December
UV Index
7
High
Temperature 26°C / 20°C
Feels Like 29°C / 21°C
Rainy Days 12
Rainfall 99 mm
Sunshine 10 h
Humidity 76%
Wind Speed 16 km/h
Dew Point 19°C
Hottest Month
31°C
July
Avg Low25°C
Rain24days
Coldest Month
12°C
January
Avg High19°C
Rain6days
Driest Month
5days
November
Avg High24°C
Avg Low17°C
Windiest Month
18 km/h
April (Gusts 41)
Sea Temperature
15°C – 32°C
Warmest water: July (
31.7°C
)
Worst Time to Visit
Consider avoiding June, July, August due to extreme heat, heavy rainfall, oppressive humidity.
Sun Position
Sunrise 06:35
Daylight 13.9h
Sunset 20:30
Live conditions—
Keystone on the map · live conditions
Keystone, United States
- Continent
- Americas
- Country
- United States
- City
- Keystone
- Population
- 24K
- Elevation
- 12 m
- Coordinates
- 28.16°, -82.62°
Seasonal Breakdown
Spring
Mar–May
Avg High 27°C
Avg Low 19°C
Rain 8 days/mo
2/3 best months
Summer
Jun–Aug
Avg High 30°C
Avg Low 25°C
Rain 22 days/mo
Autumn
Sep–Nov
Avg High 27°C
Avg Low 21°C
Rain 10 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 21°C
Avg Low 14°C
Rain 6 days/mo
2/3 best months
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 19°C / 12°C . Feb: 22°C / 15°C . Mar: 24°C / 17°C . Apr: 27°C / 19°C . May: 29°C / 22°C . Jun: 30°C / 25°C . Jul: 31°C / 25°C . Aug: 30°C / 26°C . Sep: 30°C / 24°C . Oct: 27°C / 22°C . Nov: 24°C / 17°C . Dec: 22°C / 15°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 62 mm. Feb: 62 mm. Mar: 38 mm. Apr: 58 mm. May: 89 mm. Jun: 162 mm. Jul: 199 mm. Aug: 190 mm. Sep: 170 mm. Oct: 73 mm. Nov: 36 mm. Dec: 53 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 73%. Feb: 78%. Mar: 72%. Apr: 69%. May: 71%. Jun: 79%. Jul: 81%. Aug: 82%. Sep: 81%. Oct: 76%. Nov: 74%. Dec: 77%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 17 km/h . Feb: 17 km/h . Mar: 18 km/h . Apr: 18 km/h . May: 16 km/h . Jun: 14 km/h . Jul: 13 km/h . Aug: 13 km/h . Sep: 14 km/h . Oct: 16 km/h . Nov: 16 km/h . Dec: 16 km/h .
Sunshine
Sunshine
Sunshine: Jan: 8h. Feb: 9h. Mar: 10h. Apr: 11h. May: 11h. Jun: 11h. Jul: 11h. Aug: 10h. Sep: 10h. Oct: 10h. Nov: 8h. Dec: 8h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 15°C . Feb: 18°C . Mar: 22°C . Apr: 24°C . May: 28°C . Jun: 30°C . Jul: 32°C . Aug: 32°C . Sep: 30°C . Oct: 26°C . Nov: 22°C . Dec: 18°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 5. Feb: UV 6. Mar: UV 7. Apr: UV 8. May: UV 9. Jun: UV 8. Jul: UV 8. Aug: UV 8. Sep: UV 7. Oct: UV 6. Nov: UV 5. Dec: UV 4.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending drier by about 34 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 31°C | Jul · 31°C |
| Coldest month | Jan 2025 · 9°C | Jan · 12°C |
| Wettest month | Jul 2025 · 168 mm | Jul · 199 mm |
| Windiest month | Mar 2025 · 19 km/h | Apr · 18 km/h |
Month-by-Month Weather Table
January
Good 
February best
Excellent March best
Excellent April best
Excellent May
Good June
Wet July
Wet August
Wet September
Wet October
Excellent November best
Excellent December best
Excellent | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 19°C / 12°C | 19°C / 10°C | 6days (62 mm) Good | 8h Good | 73% Muggy | 4.6 Moderate | Good | View Details |
| February best | 22°C / 15°C | 23°C / 15°C | 6days (62 mm) Good | 8.9h Good | 78% Humid | 5.8 High | Excellent | View Details |
| March best | 24°C / 17°C | 25°C / 16°C | 6days (38 mm) Good | 9.7h Good | 72% Muggy | 7.2 Very High | Excellent | View Details |
| April best | 27°C / 19°C | 29°C / 20°C | 7days (58 mm) Good | 10.8h Excellent | 69% Muggy | 8.2 Very High | Excellent | View Details |
| May | 29°C / 22°C | 33°C / 24°C | 10days (89 mm) Wet | 11.4h Excellent | 71% Muggy | 8.5 Very High | Good | View Details |
| June | 30°C / 25°C | 35°C / 29°C | 20days (162 mm) Wet | 10.9h Excellent | 79% Humid | 8.4 Very High | Wet | View Details |
| July | 31°C / 25°C | 37°C / 30°C | 24days (199 mm) Wet | 10.5h Excellent | 81% Humid | 8.3 Very High | Wet | View Details |
| August | 30°C / 26°C | 37°C / 30°C | 23days (190 mm) Wet | 9.8h Good | 82% Humid | 8 Very High | Wet | View Details |
| September | 30°C / 24°C | 35°C / 28°C | 18days (170 mm) Wet | 9.6h Good | 81% Humid | 7.4 Very High | Wet | View Details |
| October | 27°C / 22°C | 30°C / 23°C | 8days (73 mm) Wet | 9.5h Good | 76% Humid | 6.1 High | Excellent | View Details |
| November best | 24°C / 17°C | 25°C / 17°C | 5days (36 mm) Good | 8.4h Good | 74% Muggy | 5 Moderate | Excellent | View Details |
| December best | 22°C / 15°C | 22°C / 14°C | 6days (53 mm) Good | 7.9h Good | 77% Humid | 4.3 Moderate | Excellent | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Keystone are February, March, April, November, December, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Keystone, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Keystone is July, with average daytime highs of 31°C (87°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Keystone is January, with average overnight lows of 12°C (54°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Keystone is July, averaging 199mm of precipitation across 24 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Keystone runs through July, August, June, September, with the heaviest rainfall in July. Based on 10-year averages for Keystone.
Keystone receives approximately 115 sunshine hours per year. The sunniest month is May with around 11 hours. Based on climate data for Keystone.
The least favorable months to visit Keystone are June, July, August, primarily due to extreme heat, heavy rainfall, oppressive humidity. For the best conditions, consider February, March, April, November, December instead.
The annual average UV index in Keystone is 7, classified as high. SPF 30+ sunscreen, sunglasses, and seeking shade between 10:00–16:00 are strongly recommended.
Average humidity in Keystone is 76%, classified as humid. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in April, May, June, July, August, September, October, November average 28°C (82°F), which is warm and comfortable for swimming and water activities.
Average wind speeds in Keystone are 16 km/h (10 mph). The windiest month is April with peak winds reaching 18 km/h (11 mph) (gusts up to 41 km/h / 25 mph).
Keystone averages 5 clear-sky days per month with overall cloud cover around 55%. The clearest skies occur in March.
The annual average dew point in Keystone is 19°C (66°F), which feels noticeably humid. Summer months may feel slightly sticky, but conditions remain manageable for most people.
Keystone has a Humid Subtropical climate, classified as Cfa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Keystone ranges from 21°C (70°F) to 29°C (84°F) on average. Humidity and radiant heat mean it often feels warmer than the thermometer reads, especially in summer months.
June is not the best time to visit Keystone, with a climate score of 2.9/10. Consider visiting during February, March, April, November, December instead for better conditions.
For June in Keystone, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 30°C (86°F) and 20 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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