Akaiwa weather in September

In September, Akaiwa sees average daytime highs of 29°C and overnight lows near 21°C, with 168 mm of rain across 10.8 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 31°C in the first days to 26°C by the end. The sky is clear or mostly clear about 31% of the time in September, and the air most often feels muggy.

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 Akaiwa's 9th-clearest and 8th-windiest month. For the whole year in context, see Akaiwa's year-round climate.

Daytime high
29°
3rd warmest
Overnight low
21°
10th coldest
Rainfall
168 mm
10.8 wet days
Daylight
12 h 12 min
5:52 AM – 6:05 PM
Cloud cover
61%
9th clearest
Wind
9 km/h
8th windiest
Solar energy
4.34 kWh/m²
Travel score
5.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 31°C in the first days to 26°C by the end.

A typical September day in Akaiwa reaches about 29°C in the afternoon and slips back to 21°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 32°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13124
23123
33123
43123
53123
63123
73023
83022
93022
103022
113022
123022
132921
142921
152921
162921
172921
182820
192820
202820
212820
222819
232719
242719
252719
262719
272718
282618
292618
302618

How September really feels in Akaiwa

Once humidity and wind are folded in, September averages 7 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
7
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Akaiwa 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° / 405.50.39.92.4
Feb11° / 486.40.610.72.8
Mar14° / 929.30.111.74.3
Apr20° / 10°1089.7012.86.2
May24° / 15°1259.9013.86.8
Jun27° / 20°17212.2014.35.8
Jul31° / 24°18713.6014.14.0
Aug33° / 25°10810.3013.33.6
Sep29° / 21°16810.8012.25.5
Oct23° / 14°1147.7011.17.2
Nov18° / 576.1010.26.2
Dec12° / 465.30.19.73.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 52%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14951
24951
34852
44951
54951
64951
74951
84951
94852
104852
114852
124951
134852
144753
154753
164753
174753
184654
194753
204654
214753
224753
234753
244852
254852
264951
274852
284852
294852
304951

Chance of precipitation in September

Any precipitation

Akaiwa gets around 168 mm of rain over 10.8 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 37% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
137
237
337
437
537
637
737
837
937
1037
1137
1237
1336
1436
1536
1635
1735
1835
1935
2034
2134
2234
2334
2434
2534
2634
2733
2833
2933
3033

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 25% of days. Sticky, muggy-or-worse air turns up on roughly 53% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1041524488
2141625477
3151726466
4151826446
5151827435
6161928415
7262029395
8272129374
9272230354
10382230334
11392330314
124102430294
134112430273
145122530253
156132629233
167142629213
178152728203
189162727183
1910172726172
2011192825152
2112202824142
2213212923132
2313222922112
2414232921102
251524292191
261625292081
271727291971
281827291871
292028291761
302129281651

Wind in September

Winds average 9 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

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 5:41 AM to 6:02 AM, and sunset from 6:27 PM to 5:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:416:27
212.75:416:25
312.75:426:24
412.75:436:22
512.65:446:21
612.65:446:19
712.55:456:18
812.55:466:17
912.55:476:15
1012.45:476:14
1112.45:486:12
1212.45:496:11
1312.35:506:09
1412.35:506:08
1512.35:516:06
1612.25:526:05
1712.25:536:03
1812.15:536:02
1912.15:546:00
2012.15:555:59
2112.05:565:57
2212.05:565:56
2312.05:575:54
2411.95:585:53
2511.95:595:51
2611.85:595:50
2711.86:005:48
2811.86:015:47
2911.76:025:45
3011.76:025:44

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.34 kWh/m².

For context, solar energy here swings from a low near 2.41 kWh/m² to a high of 5.74 kWh/m² in May across the year — September's 4.34 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.8Bright
54.7Bright
64.7Bright
74.6Bright
84.6Bright
94.6Bright
104.5Bright
114.5Bright
124.5Bright
134.4Bright
144.4Bright
154.4Bright
164.3Bright
174.3Bright
184.3Bright
194.3Bright
204.2Bright
214.2Bright
224.2Bright
234.1Bright
244.1Bright
254.1Bright
264.0Bright
274.0Bright
284.0Bright
294.0Moderate
304.0Moderate
Planning a trip in September

Hazard calendar for Akaiwa

In seasonPeak

In September, Akaiwa sits inside its pacific typhoon and rainy season season. The full year is below, with each hazard's peak months called out.

Akaiwa sits in the Pacific typhoon belt; the season peaks July–October.

Akaiwa's rainy season runs March–October, when most of the year's rain falls.

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

Is September a good time to visit Akaiwa?

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

5.5
Sightseeing
6th-best month of the year
6.6
Beach & pool
1st-best month of the year

September is a reasonable time to visit Akaiwa for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Akaiwa in September

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

In September, Akaiwa sees daytime highs around 29°C and nights near 21°C. Pack light clothes. Worth having: rain gear. About 11 days see rain.

light clothesrain gear

Sea temperature near Akaiwa in September

The nearest coast averages about 26°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 38 km away) is warmest in August at about 27°C and coldest in February near 13°C.

It's comfortable for a long swim from Jun 7 to Nov 12 — about 5.2 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar13Bracing
Apr15Bracing
May17Cool
Jun21Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct24Refreshing
Nov20Cool
Dec16Cool

UV index in Akaiwa 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 Akaiwa peaks around July 13 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highModerateJul 13UV 10Dec 22UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5High
Apr7Very high
May8Very high
Jun10Very high
Jul10Extreme
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Akaiwa 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 Akaiwa is worst in April — around 23 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (October, 12 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1422 µg/m³Oct 1613 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb17Moderate
Mar21Moderate
Apr23Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug15Moderate
Sep13Moderate
Oct12Moderate
Nov13Moderate
Dec13Moderate
Location & terrain

Where is Akaiwa?

Akaiwa sits at 34.8°N, 134.0°E, 47 m above sea level, in Japan. The nearest listed city is Okayama, 20 km away.

Topography around Akaiwa

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Akaiwa.

Within 3 km, the terrain around Akaiwa has significant variations in elevation — a maximum elevation change of 251 m around an average of 102 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 518 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,692 m.

The land around Akaiwa is covered by trees (74%) within 3 km, trees (76%) within 16 km, and trees (65%) and water (23%) within 80 km.

3 km
251 m
16 km
518 m
80 km
1,692 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Okayama 20 km · Bizen 20 km · Setouchi 20 km · Hayashino 24 km · Tsuyama 27 km · Sōja 29 km · Kamigōri 32 km · Tamano 33 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 Akaiwa (34.8099°, 134.0215°, elevation 47 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).