Kuroiso weather in September

In September, Kuroiso sees average daytime highs of 24°C and overnight lows near 17°C, with 227 mm of rain across 16.4 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 26°C in the first days to 21°C by the end. The sky is clear or mostly clear about 17% 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 Kuroiso's 10th-clearest and 9th-windiest month. For the whole year in context, see Kuroiso's year-round climate.

Daytime high
24°
3rd warmest
Overnight low
17°
10th coldest
Rainfall
227 mm
16.4 wet days
Daylight
12 h 12 min
5:27 AM – 5:41 PM
Cloud cover
72%
10th clearest
Wind
6 km/h
9th windiest
Solar energy
3.53 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 26°C in the first days to 21°C by the end.

A typical September day in Kuroiso reaches about 24°C in the afternoon and slips back to 17°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 19°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)
12619
22619
32619
42619
52519
62519
72518
82518
92518
102518
112518
122418
132417
142417
152417
162417
172316
182316
192316
202316
212216
222215
232215
242215
252215
262214
272114
282114
292114
302114

How September really feels in Kuroiso

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.

Kuroiso weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -3°619.389.80.0
Feb / -2°568.86.210.60.2
Mar / 11113.35.111.71.8
Apr15° / 13013.11.112.94.1
May20° / 10°14913.9013.95.6
Jun23° / 15°17616.8014.55.3
Jul26° / 19°24021.1014.34.8
Aug27° / 20°19018.4013.45.0
Sep24° / 17°22716.4012.35.5
Oct18° / 10°185140115.2
Nov13° / 889.40.3103.5
Dec / -0°609.64.19.51.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 69%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13169
23070
33169
43169
53169
63169
73070
83070
93169
103169
113070
123070
133070
143070
153070
163169
173169
183070
193169
203169
213169
223169
233268
243367
253367
263367
273466
283466
293565
303565

Chance of precipitation in September

Any precipitation

Kuroiso gets around 227 mm of rain over 16.4 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 56% and peaks near 60% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
160
260
360
460
559
659
759
858
958
1058
1158
1257
1357
1456
1556
1655
1755
1855
1954
2054
2153
2253
2352
2452
2552
2651
2751
2851
2951
3051

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 29% of days. Sticky, muggy-or-worse air turns up on roughly 33% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
118294122
218304120
319314019
429313918
5210323917
6311333816
7312333715
8413333614
9514343413
10615343312
11716343211
12818333010
13101933299
14112033278
15132232267
16152331246
17162531236
18182630215
19202729194
20222928183
21243027163
22263126152
23283225132
24303324122
25323423101
2634352291
2736352081
2837361971
2939361860
3041361750

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
257calm
267calm
277calm
287calm
297calm
307calm

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 5:15 AM to 5:39 AM, and sunset from 6:04 PM to 5:19 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:156:04
212.85:156:03
312.85:166:01
412.75:176:00
512.75:185:58
612.65:195:57
712.65:205:55
812.65:205:54
912.55:215:52
1012.55:225:51
1112.45:235:49
1212.45:245:47
1312.45:255:46
1412.35:255:44
1512.35:265:43
1612.25:275:41
1712.25:285:40
1812.25:295:38
1912.15:305:36
2012.15:315:35
2112.05:315:33
2212.05:325:32
2311.95:335:30
2411.95:345:28
2511.95:355:27
2611.85:365:25
2711.85:365:24
2811.75:375:22
2911.75:385:21
3011.75:395:19

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.53 kWh/m².

For context, solar energy here swings from a low near 2.25 kWh/m² to a high of 5.19 kWh/m² in May across the year — September's 3.53 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.9Moderate
23.9Moderate
33.8Moderate
43.8Moderate
53.8Moderate
63.8Moderate
73.7Moderate
83.7Moderate
93.7Moderate
103.6Moderate
113.6Moderate
123.6Moderate
133.6Moderate
143.5Moderate
153.5Moderate
163.5Moderate
173.5Moderate
183.4Moderate
193.4Moderate
203.4Moderate
213.4Moderate
223.3Moderate
233.3Moderate
243.3Moderate
253.3Moderate
263.2Moderate
273.2Moderate
283.2Moderate
293.2Moderate
303.2Moderate
Planning a trip in September

Hazard calendar for Kuroiso

In seasonPeak

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

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

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

Is September a good time to visit Kuroiso?

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

5.5
Sightseeing
2nd-best month of the year
4.4
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Kuroiso for sightseeing.

What to pack for Kuroiso in September

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

In September, Kuroiso sees daytime highs around 24°C and nights near 17°C. Pack rain gear. Worth having: light clothes. About 16 days see rain.

rain gearlight clothes

UV index in Kuroiso 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 Kuroiso peaks around July 17 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 17UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep9Very high
Oct6High
Nov3Moderate
Dec2Low

Air quality in Kuroiso 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 Kuroiso is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (December, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 189 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun16Moderate
Jul14Moderate
Aug13Moderate
Sep11Good
Oct11Good
Nov10Good
Dec9Good
Location & terrain

Where is Kuroiso?

Kuroiso sits at 37.0°N, 140.1°E, 301 m above sea level, in Japan. The nearest listed city is Nasushiobara, 2.0 km away.

Topography around Kuroiso

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

Within 3 km, the terrain around Kuroiso has only modest variations in elevation — a maximum elevation change of 113 m around an average of 299 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,299 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,551 m.

The land around Kuroiso is covered by artificial surfaces (38%), trees (30%) and cropland (30%) within 3 km, trees (61%) and cropland (26%) within 16 km, and trees (75%) within 80 km.

3 km
113 m
16 km
1,299 m
80 km
2,551 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Nasushiobara 2.0 km · Nasu 9.0 km · Ōtawara 11 km · Yaita 21 km · Kumakura 23 km · Ogawa 25 km · Shirakawa 25 km · Sakura 28 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 Kuroiso (36.9667°, 140.05°, elevation 301 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. 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).