Innoshima, Japan experiences average highs of 19°C (66°F) and lows of 13°C (55°F) throughout the year. Rainfall is moderate, averaging about 9 rainy days per month. Average highs have stayed broadly stable across the available records.
Innoshima, Japan Weather & Climate 2026
Monthly climate averages for Innoshima, Japan. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: Mar–Sep At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
6.2/10
Best: May, June, October, November
UV Index
5
Low
Temperature 19°C / 13°C
Feels Like 19°C / 13°C
Rainy Days 9
Rainfall 113 mm
Sunshine 8 h
Humidity 73%
Wind Speed 15 km/h
Dew Point 11°C
Snow Days 3 days
Frost Days 3 days
Hottest Month
31°C
August
Avg Low 25°C
Rain 11 days
Coldest Month
3°C
January
Avg High 9°C
Rain 5 days
Driest Month
5 days
January
Avg High 9°C
Avg Low 3°C
Windiest Month
18 km/h
January (Gusts 39)
Sea Temperature
10°C – 30°C
Warmest water: August (
29.5°C
)
Worst Time to Visit
Consider avoiding January, February, August, December due to less favorable weather conditions.
Sun Position
Sunrise 05:06
Daylight 14.2h
Sunset 19:20
Live conditions —
Innoshima on the map · live conditions
Innoshima, Japan
- Continent
- Asia
- Country
- Japan
- City
- Innoshima
- Population
- 26.1K
- Coordinates
- 34.28°, 133.18°
Seasonal Breakdown
Spring
Mar–May
Avg High 18°C
Avg Low 10°C
Rain 9 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 28°C
Avg Low 23°C
Rain 12 days/mo
1/3 best months
Autumn
Sep–Nov
Avg High 22°C
Avg Low 16°C
Rain 8 days/mo
2/3 best months
Winter
Dec–Feb
Avg High 9°C
Avg Low 4°C
Rain 6 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
High Low Shaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 9°C / 3°C . Feb: 9°C / 3°C . Mar: 13°C / 6°C . Apr: 18°C / 10°C . May: 22°C / 15°C . Jun: 25°C / 19°C . Jul: 29°C / 24°C . Aug: 31°C / 25°C . Sep: 27°C / 22°C . Oct: 22°C / 16°C . Nov: 16°C / 10°C . Dec: 11°C / 5°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 42 mm. Feb: 55 mm. Mar: 95 mm. Apr: 117 mm. May: 127 mm. Jun: 201 mm. Jul: 227 mm. Aug: 145 mm. Sep: 156 mm. Oct: 111 mm. Nov: 45 mm. Dec: 39 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 67%. Feb: 68%. Mar: 70%. Apr: 71%. May: 73%. Jun: 79%. Jul: 82%. Aug: 76%. Sep: 77%. Oct: 72%. Nov: 71%. Dec: 68%.
Monthly Wind Speed
Wind Speed Gusts
Bar chart showing monthly wind speed. Jan: 18 km/h . Feb: 17 km/h . Mar: 16 km/h . Apr: 15 km/h . May: 14 km/h . Jun: 13 km/h . Jul: 13 km/h . Aug: 13 km/h . Sep: 14 km/h . Oct: 14 km/h . Nov: 14 km/h . Dec: 17 km/h .
Sunshine
Sunshine
Sunshine: Jan: 8h. Feb: 8h. Mar: 9h. Apr: 9h. May: 9h. Jun: 9h. Jul: 9h. Aug: 10h. Sep: 8h. Oct: 8h. Nov: 8h. Dec: 7h.
Sea Temperature
Sea Temperature swim
Line chart showing monthly sea temperature. Jan: 12°C . Feb: 10°C . Mar: 11°C . Apr: 15°C . May: 18°C . Jun: 22°C . Jul: 27°C . Aug: 30°C . Sep: 29°C . Oct: 24°C . Nov: 20°C . Dec: 16°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 3. Feb: UV 4. Mar: UV 5. Apr: UV 6. May: UV 6. Jun: UV 6. Jul: UV 7. Aug: UV 7. Sep: UV 6. Oct: UV 5. Nov: UV 4. Dec: UV 3.
Monthly Daylight Hours
Daylight 12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow Days Snowfall
Snow Days: Jan: 4 days. Feb: 3 days. Mar: 1 days. Apr: 0 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 0 days. Dec: 2 days.
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending drier by about 31 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 31°C | Aug · 31°C |
| Coldest month | Feb 2025 · 1°C | Jan · 3°C |
| Wettest month | Jun 2025 · 250 mm | Jul · 227 mm |
| Windiest month | Feb 2025 · 20 km/h | Jan · 18 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Fair April
Good May best
Excellent June best
Excellent July
Wet August
Poor September
Good October best
Excellent November best
Excellent December
Fair | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 9°C / 3°C | 5°C / -1°C | 5days (42 mm) Good | 7.5h Good | 67% Muggy | 3.3 Moderate | Poor | View Details |
| February | 9°C / 3°C | 5°C / -1°C | 7days (55 mm) Good | 8h Good | 68% Muggy | 4.1 Moderate | Poor | View Details |
| March | 13°C / 6°C | 11°C / 3°C | 10days (95 mm) Wet | 8.5h Good | 70% Muggy | 5.1 High | Fair | View Details |
| April | 18°C / 10°C | 17°C / 9°C | 9days (117 mm) Wet | 9h Good | 71% Muggy | 6.2 High | Good | View Details |
| May best | 22°C / 15°C | 22°C / 14°C | 9days (127 mm) Wet | 9.1h Good | 73% Muggy | 6.4 High | Excellent | View Details |
| June best | 25°C / 19°C | 28°C / 21°C | 12days (201 mm) Wet | 8.5h Good | 79% Humid | 6.4 High | Excellent | View Details |
| July | 29°C / 24°C | 34°C / 28°C | 14days (227 mm) Wet | 9.4h Good | 82% Humid | 7.4 Very High | Wet | View Details |
| August | 31°C / 25°C | 36°C / 29°C | 11days (145 mm) Wet | 10.3h Excellent | 76% Humid | 7.3 Very High | Poor | View Details |
| September | 27°C / 22°C | 30°C / 25°C | 12days (156 mm) Wet | 8.1h Good | 77% Humid | 6.4 High | Good | View Details |
| October best | 22°C / 16°C | 22°C / 16°C | 8days (111 mm) Wet | 7.8h Good | 72% Muggy | 4.8 Moderate | Excellent | View Details |
| November best | 16°C / 10°C | 14°C / 8°C | 5days (45 mm) Good | 7.9h Good | 71% Muggy | 3.7 Moderate | Excellent | View Details |
| December | 11°C / 5°C | 7°C / 2°C | 6days (39 mm) Good | 7.2h Good | 68% Muggy | 3.1 Moderate | Fair | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Innoshima are May, June, October, November, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Innoshima, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Innoshima is August, with average daytime highs of 31°C (88°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Innoshima is January, with average overnight lows of 3°C (37°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Innoshima is July, averaging 227mm of precipitation across 14 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Innoshima runs through July, June, September, August, with the heaviest rainfall in July. Based on 10-year averages for Innoshima.
Innoshima receives approximately 101 sunshine hours per year. The sunniest month is August with around 10 hours. Based on climate data for Innoshima.
The least favorable months to visit Innoshima are January, February, August, December, primarily due to less favorable weather conditions. For the best conditions, consider May, June, October, November instead.
The annual average UV index in Innoshima is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Innoshima is 73%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in July, August, September, October average 27°C (81°F), which is warm and comfortable for swimming and water activities.
Yes, Innoshima receives snow. Months with snowfall average 3 snow days and 1 cm (0 in) of accumulation, with about 3 frost days during winter.
Average wind speeds in Innoshima are 15 km/h (9 mph). The windiest month is January with peak winds reaching 18 km/h (11 mph) (gusts up to 39 km/h / 24 mph).
Innoshima averages 4 clear-sky days per month with overall cloud cover around 58%. The clearest skies occur in November.
The annual average dew point in Innoshima is 11°C (52°F), which feels pleasant with low humidity. Outdoor activities are comfortable year-round from a humidity standpoint.
Innoshima 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 Innoshima ranges from 13°C (55°F) to 19°C (66°F) on average. The 'feels like' temperature closely matches the actual temperature throughout most of the year.
July is not the best time to visit Innoshima, with a climate score of 5.5/10. Consider visiting during May, June, October, November instead for better conditions.
For July in Innoshima, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 29°C (84°F) and 14 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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