Innoshima in Summer
In summer (June, July and August), Innoshima sees average daytime highs around 27°C and overnight lows near 24°C, with 455 mm of rain over about 32 wet days across the season. It is the warmest season of the year and the wettest season of the year.
Over the season highs climb from about 23°C in early June to 29°C by late August. The sky is clear or mostly clear about 26% of the time across summer, and the air most often feels oppressive.
Summer is Innoshima's 2nd-best season to visit on our travel score. For the whole year in context, see Innoshima's year-round climate.
- Avg daytime high
- 27°C
- warmest season of the year
- Avg overnight low
- 24°C
- Rainfall
- 455 mm
- 32 wet days
- Avg wind
- 10 km/h
- Travel score
- 5.7
- 2nd-best season
- Months
- Jun · Jul · Aug
Temperature in Innoshima in Summer
Over the season highs climb from about 23°C in early June to 29°C by late August.
A typical summer day in Innoshima reaches about 27°C and drops to 24°C overnight. The warmest of the three months is August, the coolest June.
How summer really feels in Innoshima
Once humidity and wind are folded in, summer brings about 40 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Innoshima weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 10° / 5° | 63 | 11.3 | 0.6 | 10 | 2.0 |
| Feb | 10° / 5° | 69 | 10.2 | 0.7 | 10.7 | 2.2 |
| Mar | 13° / 8° | 103 | 11.1 | 0 | 11.7 | 3.5 |
| Apr | 17° / 12° | 112 | 10.4 | 0 | 12.8 | 5.4 |
| May | 21° / 16° | 129 | 9.9 | 0 | 13.8 | 6.5 |
| Jun | 24° / 20° | 192 | 12.3 | 0 | 14.2 | 6.1 |
| Jul | 28° / 24° | 171 | 11.2 | 0 | 14.1 | 5.7 |
| Aug | 30° / 26° | 93 | 8.4 | 0 | 13.3 | 5.3 |
| Sep | 27° / 23° | 153 | 10.7 | 0 | 12.2 | 6.3 |
| Oct | 22° / 18° | 127 | 8.8 | 0 | 11.1 | 7.0 |
| Nov | 17° / 12° | 67 | 8.2 | 0 | 10.2 | 5.6 |
| Dec | 12° / 8° | 71 | 10.6 | 0.2 | 9.8 | 3.2 |
Cloud cover in Summer
The sky is clear or mostly clear about 26% of the time across summer.
Chance of precipitation in Summer
Innoshima gets around 455 mm of rain over 32 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 10 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 06 min in early June to 12 h 48 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.1 kWh/m².
Hazard calendar for Innoshima
In summer, Innoshima overlaps its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Innoshima sits in the Pacific typhoon belt; the season peaks July–October.
Is summer a good time to visit Innoshima?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Innoshima for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Innoshima in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Innoshima sees daytime highs around 27°C and nights near 24°C. Pack light clothes. Worth having: rain gear and sun protection. About 32 days see rain.
Sea temperature near Innoshima in Summer
The nearest coast averages about 25°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 18 km away) is warmest in August at about 28°C and coldest in February near 13°C.
It's comfortable for a long swim from Jun 3 to Nov 14 — about 5.4 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 15 | 13 | 13 | 15 | 18 | 22 | 25 | 28 | 27 | 24 | 20 | 17 |
| Comfort | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Warm | Warm | Warm | Refreshing | Cool | Cool |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 15 | Bracing |
| Feb | 13 | Bracing |
| Mar | 13 | Bracing |
| Apr | 15 | Cool |
| May | 18 | Cool |
| Jun | 22 | Refreshing |
| Jul | 25 | Warm |
| Aug | 28 | Warm |
| Sep | 27 | Warm |
| Oct | 24 | Refreshing |
| Nov | 20 | Cool |
| Dec | 17 | Cool |
UV index in Innoshima in Summer
Clear-sky midday UV across summer averages around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Innoshima peaks around July 15 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 4 | 5 | 7 | 8 | 10 | 10 | 9 | 9 | 6 | 4 | 3 |
| Level | Moderate | Moderate | High | Very high | Very high | Very high | Extreme | Very high | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 4 | Moderate |
| Mar | 5 | High |
| Apr | 7 | Very high |
| May | 8 | Very high |
| Jun | 10 | Very high |
| Jul | 10 | Extreme |
| Aug | 9 | Very high |
| Sep | 9 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Air quality in Innoshima in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Innoshima is worst in April — around 24 µg/m³ PM2.5 (moderate), about 1.7× the cleanest month (December, 14 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 16 | 19 | 23 | 24 | 22 | 20 | 17 | 17 | 16 | 14 | 15 | 14 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 16 | Moderate |
| Feb | 19 | Moderate |
| Mar | 23 | Moderate |
| Apr | 24 | Moderate |
| May | 22 | Moderate |
| Jun | 20 | Moderate |
| Jul | 17 | Moderate |
| Aug | 17 | Moderate |
| Sep | 16 | Moderate |
| Oct | 14 | Moderate |
| Nov | 15 | Moderate |
| Dec | 14 | Moderate |
Where is Innoshima?
Innoshima sits at 34.3°N, 133.2°E, 33 m above sea level, in Japan. The nearest listed city is Onomichi, 15 km away.
Topography around Innoshima
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Innoshima.
Within 3 km, the terrain around Innoshima has significant variations in elevation — a maximum elevation change of 379 m around an average of 32 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 473 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,900 m.
The land around Innoshima is covered by water (45%) and trees (40%) within 3 km, water (66%) and trees (27%) within 16 km, and trees (62%) and water (26%) within 80 km.
Japan travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 100 V · 50 / 60 Hz
- Prices
- ≈ 65% of US
- price level, 2025
- GDP per capita
- $35,951
- 2025
- Happiness
- 6.1 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.2
- per 100k, 2023
- Road deaths
- 3.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very low
- EF EPI 446
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Innoshima (34.2833°, 133.1833°, elevation 33 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.