Ōtawara weather in September

In September, Ōtawara sees average daytime highs of 26°C and overnight lows near 18°C, with 193 mm of rain across 15.3 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 28°C in the first days to 23°C by the end. The sky is clear or mostly clear about 16% 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 Ōtawara's 9th-clearest and 8th-windiest month. For the whole year in context, see Ōtawara's year-round climate.

Daytime high
26°
3rd warmest
Overnight low
18°
10th coldest
Rainfall
193 mm
15.3 wet days
Daylight
12 h 12 min
5:27 AM – 5:41 PM
Cloud cover
71%
9th clearest
Wind
6 km/h
8th windiest
Solar energy
3.52 kWh/m²
Travel score
5.6
out of 10

Ōtawara is city in Tochigi Prefecture, Japan.

Density
203/km²
people per km²
Founded
1954

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 28°C in the first days to 23°C by the end.

A typical September day in Ōtawara reaches about 26°C in the afternoon and slips back to 18°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 21°C and 30°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12821
22821
32821
42821
52820
62720
72720
82720
92720
102720
112719
122619
132619
142619
152619
162618
172518
182518
192518
202517
212517
222417
232417
242417
252416
262416
272316
282316
292316
302315

How September really feels in Ōtawara

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.

Ōtawara 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 / -1°547.13.19.81.2
Feb / -0°537.62.810.61.6
Mar12° / 10412.62.211.73.0
Apr17° / 12112.40.512.95.1
May22° / 12°14213.4013.96.0
Jun25° / 17°16316.2014.55.5
Jul28° / 21°21219.7014.34.4
Aug29° / 22°16216.7013.44.4
Sep26° / 18°19315.3012.35.6
Oct20° / 12°16912.90115.9
Nov15° / 808.40.1104.7
Dec10° / 516.80.99.52.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 16% 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 68%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13268
23268
33268
43367
53367
63268
73268
83268
93169
103268
113169
123169
133169
143169
153169
163070
173070
183070
193169
203070
213169
223169
233169
243268
253268
263367
273367
283466
293565
303565

Chance of precipitation in September

Any precipitation

Ōtawara gets around 193 mm of rain over 15.3 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 52% and peaks near 55% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
154
254
354
455
555
655
755
854
954
1054
1154
1254
1353
1453
1552
1652
1751
1851
1950
2050
2149
2249
2349
2448
2548
2648
2748
2848
2948
3048

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 28% of days. Sticky, muggy-or-worse air turns up on roughly 48% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1041537422
2041637402
3051737392
4051837382
5061937362
6162037351
7172136331
8182236321
9192336301
102102435281
112112535271
123122634250
134132733230
145142833210
156152932190
167163031170
178173030150
189183128140
1911193227120
2012203225100
211421322490
221523332270
231724332160
241825331950
251926331740
262127321640
272229321430
282430311320
292531301220
302632291120

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 6 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
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 5:15 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
212.85:166:03
312.75:166:01
412.75:176:00
512.75:185:58
612.65:195:57
712.65:205:55
812.65:215:54
912.55:215:52
1012.55:225:51
1112.45:235:49
1212.45:245:47
1312.45:255:46
1412.35:265:44
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
2411.95:345:29
2511.95:355:27
2611.85:365:25
2711.85:375:24
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 3.52 kWh/m².

For context, solar energy here swings from a low near 2.33 kWh/m² to a high of 5.11 kWh/m² in May across the year — September's 3.52 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
213.3Moderate
223.3Moderate
233.3Moderate
243.3Moderate
253.3Moderate
263.2Moderate
273.2Moderate
283.2Moderate
293.2Moderate
303.1Moderate
Planning a trip in September

Is September a good time to visit Ōtawara?

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

5.6
Sightseeing
3rd-best month of the year
5.2
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Ōtawara for sightseeing.

What to pack for Ōtawara in September

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

In September, Ōtawara sees daytime highs around 26°C and nights near 18°C. Pack rain gear. Worth having: light clothes. About 15 days see rain.

rain gearlight clothes

UV index in Ōtawara 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 Ōtawara 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 Ōtawara 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 Ōtawara 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 Ōtawara?

Ōtawara sits at 36.9°N, 140.0°E, 205 m above sea level, in Japan. The nearest listed city is Kuroiso, 11 km away.

Topography around Ōtawara

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

Within 3 km, the terrain around Ōtawara has only modest variations in elevation — a maximum elevation change of 98 m around an average of 210 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 783 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,552 m.

The land around Ōtawara is covered by cropland (46%) and artificial surfaces (34%) within 3 km, trees (51%) and cropland (33%) within 16 km, and trees (71%) within 80 km.

3 km
98 m
16 km
783 m
80 km
2,552 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Kuroiso 11 km · Yaita 12 km · Nasushiobara 13 km · Ogawa 16 km · Sakura 17 km · Nasu 20 km · Ujiie 21 km · Karasuyama 26 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 Ōtawara (36.8667°, 140.0333°, elevation 205 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).