Marathon, United States experiences average highs of 26°C (79°F) and lows of 25°C (77°F) throughout the year. Rainfall is moderate, averaging about 10 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.
Marathon, United States Weather & Climate 2026
Monthly climate averages for Marathon, 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
7.2/10
Best: January, February, March, November, December
UV Index
7
High
Temperature 26°C / 25°C
Feels Like 30°C / 26°C
Rainy Days 10
Rainfall 78 mm
Sunshine 10 h
Humidity 77%
Wind Speed 26 km/h
Dew Point 21°C
Hottest Month
30°C
August
Avg Low28°C
Rain16days
Coldest Month
20°C
January
Avg High23°C
Rain6days
Driest Month
4days
February
Avg High24°C
Avg Low22°C
Windiest Month
29 km/h
January (Gusts 41)
Sea Temperature
23°C – 31°C
Warmest water: August (
31.4°C
)
Worst Time to Visit
Consider avoiding July, August, September due to heavy rainfall, oppressive humidity.
Sun Position
Sunrise 06:36
Daylight 13.7h
Sunset 20:16
Live conditions—
Marathon on the map · live conditions
Marathon, United States
- Continent
- Americas
- Country
- United States
- City
- Marathon
- Population
- 8.8K
- Elevation
- 1 m
- Coordinates
- 24.71°, -81.09°
Seasonal Breakdown
Spring
Mar–May
Avg High 26°C
Avg Low 24°C
Rain 6 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 29°C
Avg Low 27°C
Rain 15 days/mo
Autumn
Sep–Nov
Avg High 27°C
Avg Low 26°C
Rain 13 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 24°C
Avg Low 22°C
Rain 5 days/mo
3/3 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: 23°C / 20°C . Feb: 24°C / 22°C . Mar: 24°C / 23°C . Apr: 26°C / 24°C . May: 27°C / 26°C . Jun: 29°C / 27°C . Jul: 29°C / 28°C . Aug: 30°C / 28°C . Sep: 29°C / 27°C . Oct: 28°C / 26°C . Nov: 26°C / 24°C . Dec: 24°C / 22°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 39 mm. Feb: 24 mm. Mar: 30 mm. Apr: 33 mm. May: 94 mm. Jun: 137 mm. Jul: 75 mm. Aug: 113 mm. Sep: 171 mm. Oct: 119 mm. Nov: 48 mm. Dec: 51 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 76%. Feb: 77%. Mar: 74%. Apr: 75%. May: 76%. Jun: 80%. Jul: 78%. Aug: 78%. Sep: 79%. Oct: 78%. Nov: 76%. Dec: 77%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 29 km/h . Feb: 28 km/h . Mar: 28 km/h . Apr: 28 km/h . May: 25 km/h . Jun: 23 km/h . Jul: 22 km/h . Aug: 23 km/h . Sep: 23 km/h . Oct: 28 km/h . Nov: 27 km/h . Dec: 28 km/h .
Sunshine
Sunshine
Sunshine: Jan: 9h. Feb: 10h. Mar: 11h. Apr: 12h. May: 12h. Jun: 12h. Jul: 12h. Aug: 11h. Sep: 10h. Oct: 10h. Nov: 9h. Dec: 9h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 23°C . Feb: 24°C . Mar: 25°C . Apr: 26°C . May: 29°C . Jun: 30°C . Jul: 31°C . Aug: 31°C . Sep: 31°C . Oct: 29°C . Nov: 27°C . Dec: 25°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 5. Feb: UV 7. Mar: UV 8. Apr: UV 9. May: UV 9. Jun: UV 8. Jul: UV 8. Aug: UV 8. Sep: UV 8. Oct: UV 7. Nov: UV 6. Dec: UV 5.
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 wetter by about 14 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | — | Aug · 30°C |
| Coldest month | — | Jan · 20°C |
| Wettest month | Sep 2025 · 230 mm | Sep · 171 mm |
| Windiest month | Apr 2025 · 31 km/h | Jan · 29 km/h |
Month-by-Month Weather Table
January best
Excellent 
February best
Excellent March best
Excellent April
Excellent May
Good June
Fair July
Poor August
Poor September
Poor October
Good November best
Excellent December best
Excellent | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January best | 23°C / 20°C | 24°C / 19°C | 6days (39 mm) Good | 9h Good | 76% Humid | 5.3 High | Excellent | View Details |
| February best | 24°C / 22°C | 25°C / 22°C | 4days (24 mm) Good | 10.1h Excellent | 77% Humid | 6.5 High | Excellent | View Details |
| March best | 24°C / 23°C | 26°C / 22°C | 4days (30 mm) Good | 10.7h Excellent | 74% Muggy | 7.8 Very High | Excellent | View Details |
| April | 26°C / 24°C | 28°C / 24°C | 6days (33 mm) Good | 11.5h Excellent | 75% Muggy | 8.5 Very High | Excellent | View Details |
| May | 27°C / 26°C | 31°C / 27°C | 9days (94 mm) Wet | 11.7h Excellent | 76% Humid | 8.8 Very High | Good | View Details |
| June | 29°C / 27°C | 34°C / 30°C | 15days (137 mm) Wet | 11.5h Excellent | 80% Humid | 8.3 Very High | Fair | View Details |
| July | 29°C / 28°C | 35°C / 31°C | 14days (75 mm) Wet | 11.9h Excellent | 78% Humid | 8.4 Very High | Poor | View Details |
| August | 30°C / 28°C | 35°C / 31°C | 16days (113 mm) Wet | 11.1h Excellent | 78% Humid | 8.2 Very High | Poor | View Details |
| September | 29°C / 27°C | 34°C / 31°C | 17days (171 mm) Wet | 10.3h Excellent | 79% Humid | 7.8 Very High | Poor | View Details |
| October | 28°C / 26°C | 31°C / 28°C | 15days (119 mm) Wet | 9.7h Good | 78% Humid | 6.8 High | Good | View Details |
| November best | 26°C / 24°C | 28°C / 24°C | 6days (48 mm) Good | 9.4h Good | 76% Humid | 5.6 High | Excellent | View Details |
| December best | 24°C / 22°C | 26°C / 22°C | 6days (51 mm) Good | 8.9h Good | 77% Humid | 4.8 Moderate | Excellent | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Marathon are January, February, March, November, December, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Marathon, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Marathon is August, with average daytime highs of 30°C (85°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Marathon is January, with average overnight lows of 20°C (69°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Marathon is September, averaging 171mm of precipitation across 17 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Marathon runs through September, August, June, October, with the heaviest rainfall in September. Based on 10-year averages for Marathon.
Marathon receives approximately 126 sunshine hours per year. The sunniest month is July with around 12 hours. Based on climate data for Marathon.
The least favorable months to visit Marathon are July, August, September, primarily due to heavy rainfall, oppressive humidity. For the best conditions, consider January, February, March, November, December instead.
The annual average UV index in Marathon is 7, classified as high. SPF 30+ sunscreen, sunglasses, and seeking shade between 10:00–16:00 are strongly recommended.
Average humidity in Marathon is 77%, classified as humid. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in January, February, March, April, May, June, July, August, September, October, November, December average 28°C (82°F), which is warm and comfortable for swimming and water activities.
Average wind speeds in Marathon are 26 km/h (16 mph). The windiest month is January with peak winds reaching 29 km/h (18 mph) (gusts up to 41 km/h / 26 mph).
Marathon averages 6 clear-sky days per month with overall cloud cover around 50%. The clearest skies occur in March.
The annual average dew point in Marathon is 21°C (70°F), which feels muggy and uncomfortable. Expect heavy perspiration during warmer months — stay hydrated and take breaks in air-conditioned spaces.
Marathon has a Tropical Monsoon climate, classified as Am under the Köppen system. Tropical climates are warm year-round with high rainfall and temperatures rarely dropping below 18°C (64°F).
The 'feels like' temperature in Marathon ranges from 26°C (79°F) to 30°C (86°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 Marathon, with a climate score of 5.3/10. Consider visiting during January, February, March, November, December instead for better conditions.
For June in Marathon, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 29°C (83°F) and 15 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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