Minamiuonuma weather in September

In September, Minamiuonuma sees average daytime highs of 23°C and overnight lows near 15°C, with 216 mm of rain across 18.2 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 25°C in the first days to 20°C by the end. The sky is clear or mostly clear about 14% of the time in September, and the air most often feels humid.

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

Daytime high
23°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
216 mm
18.2 wet days
Daylight
12 h 12 min
5:32 AM – 5:46 PM
Cloud cover
73%
8th clearest
Wind
5 km/h
9th windiest
Solar energy
3.87 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 25°C in the first days to 20°C by the end.

A typical September day in Minamiuonuma reaches about 23°C in the afternoon and slips back to 15°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 18°C and 27°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°151015202530
Avg high (°C)Avg low (°C)
12518
22518
32518
42518
52517
62517
72417
82417
92417
102417
112416
122416
132316
142316
152315
162315
172215
182215
192215
202214
212214
222114
232114
242113
252113
262113
272013
282012
292012
302012

How September really feels in Minamiuonuma

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.

Minamiuonuma 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 daysSnow daysDaylight (hours)Travel score
Jan / -6°22925.425.39.70.0
Feb / -5°17721.320.310.60.0
Mar / -3°17621.217.311.70.3
Apr12° / 13916.6512.92.7
May19° / 16115.90.3145.1
Jun22° / 14°20118.4014.55.0
Jul26° / 18°29222.5014.34.7
Aug27° / 19°21720.2013.45.0
Sep23° / 15°21618.2012.35.2
Oct17° / 20117.50.3114.3
Nov10° / 16818.76.4101.9
Dec / -4°21023.319.49.50.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 14% 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 70%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13169
23169
33169
43169
53070
63070
73070
83169
93070
103070
113070
122971
133070
143070
153070
163070
173070
182971
192971
202971
212971
222971
232971
243070
253070
262971
272872
282872
292872
302971

Chance of precipitation in September

Any precipitation

Minamiuonuma gets around 216 mm of rain over 18.2 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 62% and peaks near 67% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
167
267
366
466
566
666
766
865
965
1064
1164
1263
1363
1462
1561
1660
1760
1859
1958
2058
2158
2257
2357
2457
2558
2658
2758
2859
2959
3059

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the humid band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 23% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
121137483
221238462
321338452
431439432
531539412
641639402
741839381
851939361
962039341
1072239321
1192338301
12102438271
13122537251
14142736230
15162835210
16182934190
17203033170
18223131150
19253230130
20273328120
21303327100
2233342590
2335342370
2438352160
2540351950
2643361840
2745361640
2847361430
2949351320
3052351120

Wind in September

Winds average 5 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

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 5:19 AM to 5:44 AM, and sunset from 6:09 PM to 5:24 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:196:09
212.85:206:08
312.85:216:06
412.75:226:05
512.75:236:03
612.65:236:02
712.65:246:00
812.65:255:58
912.55:265:57
1012.55:275:55
1112.45:285:54
1212.45:285:52
1312.45:295:51
1412.35:305:49
1512.35:315:47
1612.25:325:46
1712.25:335:44
1812.25:345:43
1912.15:345:41
2012.15:355:39
2112.05:365:38
2212.05:375:36
2311.95:385:35
2411.95:395:33
2511.95:395:32
2611.85:405:30
2711.85:415:28
2811.75:425:27
2911.75:435:25
3011.75:445:24

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.87 kWh/m².

For context, solar energy here swings from a low near 2.08 kWh/m² to a high of 5.62 kWh/m² in May across the year — September's 3.87 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.3Bright
44.2Bright
54.2Bright
64.2Bright
74.1Bright
84.1Bright
94.0Bright
104.0Bright
114.0Moderate
123.9Moderate
133.9Moderate
143.9Moderate
153.8Moderate
163.8Moderate
173.8Moderate
183.7Moderate
193.7Moderate
203.7Moderate
213.7Moderate
223.6Moderate
233.6Moderate
243.6Moderate
253.5Moderate
263.5Moderate
273.5Moderate
283.5Moderate
293.5Moderate
303.4Moderate
Planning a trip in September

Hazard calendar for Minamiuonuma

In seasonPeak

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

Minamiuonuma 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 Minamiuonuma?

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

5.2
Sightseeing
1st-best month of the year
3.8
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Minamiuonuma for sightseeing.

What to pack for Minamiuonuma in September

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

In September, Minamiuonuma sees daytime highs around 23°C and nights near 15°C. Pack rain gear. Worth having: light clothes. About 18 days see rain.

rain gearlight clothes

Sea temperature near Minamiuonuma in September

The nearest coast averages about 25°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 39 km away) is warmest in August at about 27°C and coldest in March near 10°C.

It's comfortable for a long swim from Jun 21 to Oct 31 — about 4.4 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb11Bracing
Mar10Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug27Warm
Sep25Warm
Oct22Refreshing
Nov18Cool
Dec15Cool

UV index in Minamiuonuma in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Minamiuonuma peaks around August 12 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 highModerateAug 12UV 10Dec 21UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug10Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Moderate

Air quality in Minamiuonuma 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 Minamiuonuma is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 1610 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug13Moderate
Sep12Good
Oct12Good
Nov11Good
Dec10Good
Location & terrain

Where is Minamiuonuma?

Minamiuonuma sits at 37.1°N, 138.9°E, 198 m above sea level, in Japan. The nearest listed city is Muikamachi, 2.0 km away.

Topography around Minamiuonuma

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

Within 3 km, the terrain around Minamiuonuma has significant variations in elevation — a maximum elevation change of 455 m around an average of 255 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,870 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,551 m.

The land around Minamiuonuma is covered by trees (52%) and cropland (26%) within 3 km, trees (76%) within 16 km, and trees (74%) within 80 km.

3 km
455 m
16 km
1,870 m
80 km
2,551 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Muikamachi 2.0 km · Shiozawa 5.0 km · Tōkamachi 11 km · Uonuma 20 km · Ojiya 25 km · Nagaoka 41 km · Kashiwazaki 43 km · Minakami 45 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 Minamiuonuma (37.0826°, 138.8741°, elevation 198 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).