Ina weather in September

In September, Ina sees average daytime highs of 23°C and overnight lows near 15°C, with 164 mm of rain across 12.5 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 25°C in the first days to 20°C by the end. The sky is clear or mostly clear about 20% of the time in September, and the air most often feels dry.

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 Ina's 10th-clearest and 11th-windiest month. For the whole year in context, see Ina's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
164 mm
12.5 wet days
Daylight
12 h 12 min
5:36 AM – 5:49 PM
Cloud cover
68%
10th clearest
Wind
5 km/h
11th windiest
Solar energy
4.02 kWh/m²
Travel score
6.1
out of 10

Ina is city in Nagano prefecture, Japan.

Density
102/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 25°C in the first days to 20°C by the end.

A typical September day in Ina 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 19°C and 26°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)
12517
22517
32517
42517
52516
62516
72416
82416
92416
102416
112416
122415
132315
142315
152315
162315
172314
182214
192214
202214
212214
222213
232113
242113
252113
262113
272112
282012
292012
302012

How September really feels in Ina

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.

Ina 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 / -8°8310.710.59.80.0
Feb / -7°889.38.310.60.0
Mar / -3°14413.27.811.70.9
Apr13° / 13312.11.912.93.6
May18° / 13711.9013.95.6
Jun22° / 14°18115.2014.45.4
Jul25° / 17°20316.5014.25.6
Aug26° / 18°12114.1013.45.9
Sep23° / 15°16412.5012.26.1
Oct17° / 17611.7011.15.2
Nov11° / 989.71.110.12.7
Dec / -4°8010.47.59.60.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% 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 63%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13763
23862
33763
43763
53763
63862
73862
83862
93862
103763
113862
123763
133763
143862
153862
163862
173862
183862
193862
203763
213862
223763
233763
243763
253763
263763
273763
283763
293862
303862

Chance of precipitation in September

Any precipitation

Ina gets around 164 mm of rain over 12.5 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 43% and peaks near 45% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
144
244
344
444
543
643
742
842
942
1041
1141
1241
1341
1441
1541
1641
1741
1841
1942
2042
2142
2243
2343
2443
2544
2644
2744
2845
2945
3045

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 37% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1928549
2929539
31030519
41230508
51331488
61432477
71632457
81833436
91933425
102134405
112434384
122634364
132934343
143134323
153433303
163733282
174032262
184332242
194631222
204831201
215130181
225429161
235629141
245828131
256127111
266227101
27652690
28662680
29682570
30702460

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 5 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
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

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 5:24 AM to 5:47 AM, and sunset from 6:12 PM to 5:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:246:12
212.85:256:10
312.75:266:09
412.75:266:07
512.65:276:06
612.65:286:04
712.65:296:03
812.55:306:01
912.55:306:00
1012.55:315:58
1112.45:325:57
1212.45:335:55
1312.35:335:54
1412.35:345:52
1512.35:355:51
1612.25:365:49
1712.25:375:48
1812.15:375:46
1912.15:385:45
2012.15:395:43
2112.05:405:42
2212.05:415:40
2312.05:415:38
2411.95:425:37
2511.95:435:35
2611.85:445:34
2711.85:455:32
2811.85:455:31
2911.75:465:29
3011.75:475:28

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.02 kWh/m².

For context, solar energy here swings from a low near 2.57 kWh/m² to a high of 5.6 kWh/m² in May across the year — September's 4.02 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.4Bright
34.4Bright
44.4Bright
54.3Bright
64.3Bright
74.3Bright
84.2Bright
94.2Bright
104.2Bright
114.1Bright
124.1Bright
134.1Bright
144.0Bright
154.0Bright
164.0Moderate
174.0Moderate
183.9Moderate
193.9Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.7Moderate
283.7Moderate
293.6Moderate
303.6Moderate
Planning a trip in September

Is September a good time to visit Ina?

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

6.1
Sightseeing
1st-best month of the year
4.6
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Ina for sightseeing.

What to pack for Ina in September

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

In September, Ina sees daytime highs around 23°C and nights near 15°C. Worth packing: light clothes and rain gear. About 13 days see rain.

light clothesrain gear

UV index in Ina 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 Ina peaks around July 14 at about 11 (extreme) — 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 highExtremeVery highModerateJul 14UV 11Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Ina 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 Ina is worst in April — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1918 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar17Moderate
Apr18Moderate
May17Moderate
Jun16Moderate
Jul13Moderate
Aug12Good
Sep10Good
Oct10Good
Nov9Good
Dec8Good
Location & terrain

Where is Ina?

Ina sits at 35.8°N, 138.0°E, 638 m above sea level, in Japan. The nearest listed city is Minamiminowa, 5.0 km away.

Topography around Ina

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

Within 3 km, the terrain around Ina has significant variations in elevation — a maximum elevation change of 417 m around an average of 678 m above sea level; within 16 km, extreme variations in elevation — a maximum elevation change of 2,406 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,069 m.

The land around Ina is covered by artificial surfaces (36%), cropland (35%) and trees (20%) within 3 km, trees (76%) within 16 km, and trees (89%) within 80 km.

3 km
417 m
16 km
2,406 m
80 km
3,069 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Minamiminowa 5.0 km · Kinoshita 9.0 km · Komagane 12 km · Tatsuno 18 km · Chino 26 km · Okaya 27 km · Suwa 27 km · Shimosuwa 29 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 Ina (35.8276°, 137.9538°, elevation 638 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).