Innoshima weather in September

In September, Innoshima sees average daytime highs of 27°C and overnight lows near 23°C, with 153 mm of rain across 10.7 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 29°C in the first days to 25°C by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Innoshima's 8th-clearest and 8th-windiest month. For the whole year in context, see Innoshima's year-round climate.

Daytime high
27°
3rd warmest
Overnight low
23°
10th coldest
Rainfall
153 mm
10.7 wet days
Daylight
12 h 12 min
5:55 AM – 6:08 PM
Cloud cover
60%
8th clearest
Wind
12 km/h
8th windiest
Solar energy
4.22 kWh/m²
Travel score
6.3
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 29°C in the first days to 25°C by the end.

A typical September day in Innoshima reaches about 27°C in the afternoon and slips back to 23°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 29°C. Set against its neighbours, September runs about 3°C cooler than August and about 5°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12925
22925
32925
42925
52824
62824
72824
82824
92824
102824
112824
122823
132723
142723
152723
162723
172723
182722
192622
202622
212622
222622
232622
242521
252521
262521
272521
282521
292521
302520

How September really feels in Innoshima

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Innoshima weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan10° / 6311.30.6102.0
Feb10° / 6910.20.710.72.2
Mar13° / 10311.1011.73.5
Apr17° / 12°11210.4012.85.4
May21° / 16°1299.9013.86.5
Jun24° / 20°19212.3014.26.1
Jul28° / 24°17111.2014.15.7
Aug30° / 26°938.4013.35.3
Sep27° / 23°15310.7012.26.3
Oct22° / 18°1278.8011.17.0
Nov17° / 12°678.2010.25.6
Dec12° / 7110.60.29.83.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15050
24852
34852
44852
54951
64951
74951
84951
94951
104951
114852
124852
134951
145050
154951
164951
175050
184951
195050
204951
215050
225050
235050
245050
255050
265248
275248
285248
295248
305248

Chance of precipitation in September

Any precipitation

Innoshima gets around 153 mm of rain over 10.7 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 35% and peaks near 36% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
134
234
335
435
535
635
735
835
935
1035
1135
1235
1335
1434
1534
1634
1735
1835
1935
2035
2135
2235
2335
2436
2536
2636
2736
2835
2935
3035

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the oppressive band about 31% of days. Sticky, muggy-or-worse air turns up on roughly 63% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1019255411
2029265310
3021027529
4021128518
5031229498
6131230477
7141331456
8141431446
9151532425
10261532405
11261632395
12271732374
13381832354
14391832334
154111932313
165122031293
175132131273
186142230263
196152230243
207162329222
217172429202
228182528192
238192628172
249202727152
259212826141
2610222926131
2710223025121
2811233124111
2912243123101
301324322290

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1212calm
1312calm
1412calm
1512calm
1612calm
1712light breeze
1812light breeze
1912light breeze
2012light breeze
2112light breeze
2212light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 5:44 AM to 6:06 AM, and sunset from 6:30 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:446:30
212.75:456:28
312.75:466:27
412.65:476:25
512.65:476:24
612.65:486:22
712.55:496:21
812.55:496:20
912.55:506:18
1012.45:516:17
1112.45:526:15
1212.45:526:14
1312.35:536:12
1412.35:546:11
1512.25:556:09
1612.25:556:08
1712.25:566:06
1812.15:576:05
1912.15:576:03
2012.15:586:02
2112.05:596:01
2212.06:005:59
2312.06:005:58
2411.96:015:56
2511.96:025:55
2611.86:035:53
2711.86:035:52
2811.86:045:50
2911.76:055:49
3011.76:065:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.22 kWh/m².

For context, solar energy here swings from a low near 2.29 kWh/m² to a high of 5.58 kWh/m² in May across the year — September's 4.22 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.6Bright
44.6Bright
54.5Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.4Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.1Bright
214.1Bright
224.1Bright
234.0Bright
244.0Bright
254.0Moderate
264.0Moderate
273.9Moderate
283.9Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Hazard calendar for Innoshima

In seasonPeak

In September, Innoshima sits inside 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.

Pacific typhoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Innoshima?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

6.3
Sightseeing
3rd-best month of the year
6.5
Beach & pool
3rd-best month of the year

September 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 September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Innoshima sees daytime highs around 27°C and nights near 23°C. Worth packing: light clothes and rain gear. About 11 days see rain.

light clothesrain gear

Sea temperature near Innoshima in September

The nearest coast averages about 27°C in September — 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.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan15Bracing
Feb13Bracing
Mar13Bracing
Apr15Cool
May18Cool
Jun22Refreshing
Jul25Warm
Aug28Warm
Sep27Warm
Oct24Refreshing
Nov20Cool
Dec17Cool

UV index in Innoshima in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJul 15UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5High
Apr7Very high
May8Very high
Jun10Very high
Jul10Extreme
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Innoshima in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September 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).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1324 µg/m³Dec 1414 µg/m³
PM2.5 (µg/m³)Level
Jan16Moderate
Feb19Moderate
Mar23Moderate
Apr24Moderate
May22Moderate
Jun20Moderate
Jul17Moderate
Aug17Moderate
Sep16Moderate
Oct14Moderate
Nov15Moderate
Dec14Moderate
Location & terrain

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.

3 km
379 m
16 km
473 m
80 km
1,900 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Onomichi 15 km · Mihara 16 km · Takehara 25 km · Fukuyama 28 km · Imabari 29 km · Shin’ichi 31 km · Fuchūchō 33 km · Kōzan 36 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
Shintoism 49%Buddhism 46%other 4%Christianity 1%

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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).