Niseko weather in September

In September, Niseko sees average daytime highs of 20°C and overnight lows near 12°C, with 141 mm of rain across 13.9 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 22°C in the first days to 18°C by the end. The sky is clear or mostly clear about 23% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Niseko's 4th-clearest and 9th-windiest month. For the whole year in context, see Niseko's year-round climate.

Daytime high
20°
3rd warmest
Overnight low
12°
10th coldest
Rainfall
141 mm
13.9 wet days
Daylight
12 h 18 min
5:23 AM – 5:40 PM
Cloud cover
66%
4th clearest
Wind
7 km/h
9th windiest
Solar energy
3.81 kWh/m²
Travel score
5.6
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 22°C in the first days to 18°C by the end.

A typical September day in Niseko reaches about 20°C in the afternoon and slips back to 12°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 17°C and 23°C. Set against its neighbours, September runs about 4°C cooler than August and about 7°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12316
22315
32315
42215
52215
62215
72214
82214
92214
102214
112114
122113
132113
142113
152113
162012
172012
182012
192012
202011
211911
221911
231911
241910
251910
261810
271810
28189
29189
30179

How September really feels in Niseko

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.

Niseko 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° / -10°5812.618.59.20.0
Feb-2° / -9°5110.415.610.30.0
Mar / -6°7113.213.911.60.0
Apr / 7511.95.213.11.7
May15° / 9412.60.314.44.3
Jun19° / 11°7710.6015.15.8
Jul23° / 16°13613.9014.86.0
Aug24° / 17°18213.8013.76.1
Sep20° / 12°14113.9012.35.6
Oct14° / 9913.70.610.83.7
Nov / -1°9214.810.19.60.6
Dec-1° / -7°7614.518.88.90.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 23% 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 60%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13664
23664
33664
43664
53664
63664
73664
83664
93664
103862
113862
123862
133961
143961
154060
164060
174060
184159
194159
204357
214357
224357
234357
244357
254456
264456
274555
284555
294456
304555

Chance of precipitation in September

Any precipitation

Niseko gets around 141 mm of rain over 13.9 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 48% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
146
246
346
447
547
647
748
848
948
1048
1148
1248
1348
1447
1547
1647
1746
1846
1946
2046
2146
2246
2346
2446
2546
2647
2747
2847
2947
3047

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 46% of days. Sticky, muggy-or-worse air turns up on roughly 9% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1143034193
2153133193
3163231183
4183330173
5193429162
6213427152
7233526142
8253524142
9273523132
10293522122
11323520111
12353519101
1338341891
1441341681
1544331581
1647321371
1750311261
1853301160
195828950
206127840
216326740
226625630
236824530
247023430
257223320
267322320
277621210
287720210
297919110
308118100

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 7 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
278calm
288calm
298calm
308calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:06 AM to 5:39 AM, and sunset from 6:08 PM to 5:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:066:08
213.05:076:06
312.95:096:04
412.95:106:02
512.85:116:00
612.85:125:59
712.75:135:57
812.75:145:55
912.65:155:53
1012.65:165:51
1112.55:175:49
1212.55:195:48
1312.45:205:46
1412.45:215:44
1512.35:225:42
1612.35:235:40
1712.25:245:38
1812.25:255:36
1912.15:265:35
2012.15:275:33
2112.05:295:31
2212.05:305:29
2311.95:315:27
2411.95:325:25
2511.85:335:23
2611.85:345:22
2711.75:355:20
2811.75:375:18
2911.65:385:16
3011.65:395:14

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.81 kWh/m².

For context, solar energy here swings from a low near 1.68 kWh/m² to a high of 5.48 kWh/m² in May across the year — September's 3.81 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.1Bright
24.1Bright
34.1Bright
44.0Bright
54.0Bright
64.0Moderate
74.0Moderate
83.9Moderate
93.9Moderate
103.9Moderate
113.9Moderate
123.9Moderate
133.8Moderate
143.8Moderate
153.8Moderate
163.8Moderate
173.8Moderate
183.8Moderate
193.7Moderate
203.7Moderate
213.7Moderate
223.7Moderate
233.6Moderate
243.6Moderate
253.6Moderate
263.6Moderate
273.5Moderate
283.5Moderate
293.5Moderate
303.4Moderate
Planning a trip in September

Hazard calendar for Niseko

In seasonPeak

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

Niseko 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 Niseko?

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

5.6
Sightseeing
4th-best month of the year
3.1
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Niseko for sightseeing.

What to pack for Niseko in September

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

In September, Niseko sees daytime highs around 20°C and nights near 12°C. Pack rain gear. About 14 days see rain.

rain gear

Sea temperature near Niseko in September

The nearest coast averages about 21°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 26 km away) is warmest in August at about 22°C and coldest in February near 6°C.

It's comfortable for a long swim from Jul 29 to Sep 25 — about 1.9 months when the water holds above 20°C.

5°10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan8Bracing
Feb6Bracing
Mar6Bracing
Apr8Bracing
May11Bracing
Jun15Bracing
Jul19Cool
Aug22Refreshing
Sep21Refreshing
Oct17Cool
Nov13Bracing
Dec10Bracing

UV index in Niseko in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Niseko peaks around August 18 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighVery highHighModerateLowAug 18UV 8Dec 20UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar3Moderate
Apr5High
May8Very high
Jun7High
Jul5Moderate
Aug9Very high
Sep6High
Oct4Moderate
Nov2Low
Dec1Low

Air quality in Niseko 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 Niseko is worst in April — around 20 µg/m³ PM2.5 (moderate), about 2.5× the cleanest month (December, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1219 µg/m³Dec 158 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb14Moderate
Mar19Moderate
Apr20Moderate
May18Moderate
Jun12Moderate
Jul11Good
Aug10Good
Sep9Good
Oct11Good
Nov9Good
Dec8Good
Location & terrain

Where is Niseko?

Niseko sits at 42.8°N, 140.7°E, 0 m above sea level, in Japan. The nearest listed city is Kutchan, 11 km away.

Topography around Niseko

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

Within 3 km, the terrain around Niseko has only modest variations in elevation — a maximum elevation change of 199 m around an average of 161 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,881 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,867 m.

The land around Niseko is covered by trees (56%) and cropland (31%) within 3 km, trees (80%) within 16 km, and water (47%) and trees (44%) within 80 km.

3 km
199 m
16 km
1,881 m
80 km
1,867 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Kutchan 11 km · Date 41 km · Yoichi 44 km · Otaru 50 km · Noboribetsu 57 km · Muroran 60 km · Sapporo 61 km · Shiraoi 61 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 Niseko (42.8089°, 140.686°, elevation 0 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).