Aira weather in September

In September, Aira sees average daytime highs of 29°C and overnight lows near 23°C, with 197 mm of rain across 14.5 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 30°C in the first days to 27°C by the end. The sky is clear or mostly clear about 29% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Aira's 6th-clearest and 11th-windiest month. For the whole year in context, see Aira's year-round climate.

Daytime high
29°
3rd warmest
Overnight low
23°
10th coldest
Rainfall
197 mm
14.5 wet days
Daylight
12 h 12 min
6:06 AM – 6:18 PM
Cloud cover
62%
6th clearest
Wind
8 km/h
11th windiest
Solar energy
4.2 kWh/m²
Travel score
5.2
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 30°C in the first days to 27°C by the end.

A typical September day in Aira reaches about 29°C in the afternoon and slips back to 23°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 31°C. Set against its neighbours, September runs about 2°C cooler than August and about 4°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13024
23024
33024
43024
53024
63024
73024
82924
92924
102923
112923
122923
132923
142923
152923
162923
172822
182822
192822
202822
212822
222822
232821
242821
252721
262721
272721
282721
292721
302720

How September really feels in Aira

Once humidity and wind are folded in, September averages 11 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
11
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.

Aira weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan11° / 819.610.22.9
Feb13° / 1049.710.83.3
Mar16° / 15312.911.84.5
Apr20° / 12°18211.512.85.9
May24° / 16°20511.713.66.4
Jun26° / 21°51419.4144.9
Jul30° / 25°3362013.93.9
Aug31° / 25°17317.513.23.8
Sep29° / 23°19714.512.25.2
Oct24° / 17°1088.611.27.2
Nov19° / 12°1118.710.46.3
Dec14° / 877.9104.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 51%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14753
24654
34654
44654
54654
64654
74654
84654
94753
104753
114852
124852
134852
144951
154951
164951
175050
185050
195050
205050
214951
225050
235050
245149
255149
265050
275050
285149
295149
305149

Chance of precipitation in September

Any precipitation

Aira gets around 197 mm of rain over 14.5 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 47% and peaks near 58% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
158
258
357
457
556
656
756
855
954
1053
1152
1251
1350
1449
1548
1647
1746
1845
1944
2043
2142
2241
2340
2440
2539
2638
2738
2837
2937
3036

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 42% of days. Sticky, muggy-or-worse air turns up on roughly 80% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1001145827
2001155826
3001165924
4002175823
5002185921
6012195820
7013205719
8013215817
9014225716
10025235515
11026245414
12137255113
13139264913
141410274712
151412284411
161513284210
17151529409
18261629388
19271830368
20272030347
21282131326
22282231306
23292432285
242102532265
252112632255
262112732234
273122832224
283132831213
293142931203
304153030193

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 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 60 minutes over September. Sunrise moves from 5:57 AM to 6:15 AM, and sunset from 6:38 PM to 5:59 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:576:38
212.75:576:37
312.65:586:35
412.65:596:34
512.65:596:33
612.56:006:31
712.56:016:30
812.56:016:29
912.46:026:27
1012.46:026:26
1112.46:036:25
1212.36:046:23
1312.36:046:22
1412.36:056:20
1512.26:066:19
1612.26:066:18
1712.26:076:16
1812.16:076:15
1912.16:086:14
2012.16:096:12
2112.06:096:11
2212.06:106:09
2312.06:116:08
2411.96:116:07
2511.96:126:05
2611.96:136:04
2711.86:136:03
2811.86:146:01
2911.86:156:00
3011.76:155:59

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.2 kWh/m².

For context, solar energy here swings from a low near 2.45 kWh/m² to a high of 5.04 kWh/m² in May across the year — September's 4.2 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.4Bright
54.4Bright
64.4Bright
74.4Bright
84.4Bright
94.3Bright
104.3Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.2Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.1Bright
234.1Bright
244.1Bright
254.1Bright
264.0Bright
274.0Bright
284.0Bright
294.0Moderate
304.0Moderate
Planning a trip in September

Hazard calendar for Aira

In seasonPeak

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

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

Aira's rainy season runs June–July, 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 Aira?

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

5.2
Sightseeing
5th-best month of the year
6.1
Beach & pool
1st-best month of the year

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

What to pack for Aira in September

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

In September, Aira sees daytime highs around 29°C and nights near 23°C. Pack light clothes and rain gear. About 15 days see rain.

light clothesrain gear

Sea temperature near Aira 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 44 km away) is warmest in August at about 28°C and coldest in February near 16°C.

It's comfortable for a long swim from May 16 to Dec 4 — about 6.7 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan17Cool
Feb16Cool
Mar17Cool
Apr18Cool
May20Refreshing
Jun23Refreshing
Jul26Warm
Aug28Warm
Sep27Warm
Oct24Warm
Nov22Refreshing
Dec19Cool

UV index in Aira in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks 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 Aira peaks around July 10 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 10UV 11Dec 23UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar7High
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug9Very high
Sep10Very high
Oct6High
Nov5Moderate
Dec3Moderate

Air quality in Aira 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 Aira is worst in April — around 23 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 12 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1423 µg/m³Oct 1012 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb19Moderate
Mar22Moderate
Apr23Moderate
May21Moderate
Jun17Moderate
Jul12Moderate
Aug14Moderate
Sep12Moderate
Oct12Moderate
Nov14Moderate
Dec13Moderate
Location & terrain

Where is Aira?

Aira sits at 31.8°N, 130.6°E, 76 m above sea level, in Japan. The nearest listed city is Kajiki, 8.0 km away.

Topography around Aira

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

Within 3 km, the terrain around Aira has significant variations in elevation — a maximum elevation change of 271 m around an average of 87 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 694 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,683 m.

The land around Aira is covered by trees (74%) within 3 km, trees (74%) within 16 km, and trees (55%) and water (37%) within 80 km.

3 km
271 m
16 km
694 m
80 km
1,683 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Kajiki 8.0 km · Hamanoichi 15 km · Kirishima 17 km · Kokubu-matsuki 17 km · Tsuruda 22 km · Umeki 23 km · Kagoshima 23 km · Ijūin 25 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 Aira (31.7743°, 130.5921°, elevation 76 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).