Komoro weather in September

In September, Komoro sees average daytime highs of 23°C and overnight lows near 15°C, with 187 mm of rain across 17.6 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 3rd-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 18% 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 Komoro's 10th-clearest and 9th-windiest month. For the whole year in context, see Komoro's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
187 mm
17.6 wet days
Daylight
12 h 12 min
5:34 AM – 5:47 PM
Cloud cover
69%
10th clearest
Wind
5 km/h
9th windiest
Solar energy
3.92 kWh/m²
Travel score
5.3
out of 10

Komoro is city in Nagano Prefecture, Japan.

Density
470/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 Komoro 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
22517
32517
42517
52517
62517
72417
82417
92416
102416
112416
122316
132316
142315
152315
162315
172215
182215
192214
202214
212214
222114
232113
242113
252113
262013
272013
282012
292012
302012

How September really feels in Komoro

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.

Komoro weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -5°557.57.89.80.0
Feb / -5°5787.110.60.0
Mar / -2°9911.77.311.71.3
Apr14° / 10212.32.312.93.9
May19° / 131150.113.95.4
Jun22° / 14°19719.8014.44.8
Jul26° / 18°22021.6014.24.8
Aug27° / 19°17421.6013.44.8
Sep23° / 15°18717.6012.25.3
Oct17° / 16112.9011.15.0
Nov11° / 647.80.610.13.0
Dec / -2°487.95.39.60.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 18% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 64%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13664
23664
33664
43664
53664
63664
73664
83565
93763
103763
113664
123565
133565
143664
153664
163565
173565
183565
193664
203565
213565
223565
233664
243664
253664
263763
273763
283763
293763
303862

Chance of precipitation in September

Any precipitation

Komoro gets around 187 mm of rain over 17.6 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 60% and peaks near 68% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
168
267
367
466
566
665
764
864
963
1063
1162
1262
1361
1461
1560
1660
1759
1859
1958
2057
2157
2256
2355
2455
2554
2654
2753
2853
2952
3052

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 32% of days. Sticky, muggy-or-worse air turns up on roughly 6% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
15245516
26255415
37265314
48265214
59275113
610275112
712284911
813294711
915304610
101631449
111831428
122032418
132232397
142532376
152733355
163033335
173333314
183633283
193833263
204133242
214432212
224732192
235131171
245331151
255630131
265829121
276128101
28632890
29652780
30682660

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 5:22 AM to 5:45 AM, and sunset from 6:10 PM to 5:26 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:226:10
212.85:226:09
312.75:236:07
412.75:246:06
512.75:256:04
612.65:266:03
712.65:276:01
812.55:276:00
912.55:285:58
1012.55:295:57
1112.45:305:55
1212.45:315:54
1312.35:315:52
1412.35:325:51
1512.35:335:49
1612.25:345:47
1712.25:355:46
1812.15:355:44
1912.15:365:43
2012.15:375:41
2112.05:385:40
2212.05:395:38
2312.05:395:37
2411.95:405:35
2511.95:415:33
2611.85:425:32
2711.85:435:30
2811.85:445:29
2911.75:445:27
3011.75:455:26

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.92 kWh/m².

For context, solar energy here swings from a low near 2.52 kWh/m² to a high of 5.67 kWh/m² in May across the year — September's 3.92 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.3Bright
34.3Bright
44.3Bright
54.3Bright
64.2Bright
74.2Bright
84.1Bright
94.1Bright
104.1Bright
114.0Bright
124.0Bright
134.0Moderate
143.9Moderate
153.9Moderate
163.9Moderate
173.8Moderate
183.8Moderate
193.8Moderate
203.8Moderate
213.7Moderate
223.7Moderate
233.7Moderate
243.6Moderate
253.6Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Komoro

In seasonPeak

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

Komoro's rainy season runs April–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 Komoro?

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

5.3
Sightseeing
2nd-best month of the year
3.9
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Komoro for sightseeing.

What to pack for Komoro in September

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

In September, Komoro 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

UV index in Komoro 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 Komoro peaks around July 18 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 highModerateJul 18UV 10Dec 22UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5High
Apr7Very high
May9Very high
Jun10Very high
Jul10Very high
Aug10Very high
Sep9Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Komoro 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 Komoro is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 1810 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug14Moderate
Sep13Moderate
Oct12Moderate
Nov11Good
Dec10Good
Location & terrain

Where is Komoro?

Komoro sits at 36.3°N, 138.4°E, 686 m above sea level, in Japan. The nearest listed city is Miyota, 7.0 km away.

Topography around Komoro

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

Within 3 km, the terrain around Komoro has significant variations in elevation — a maximum elevation change of 393 m around an average of 720 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,103 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,141 m.

The land around Komoro is covered by artificial surfaces (33%), trees (31%) and cropland (23%) within 3 km, trees (63%) within 16 km, and trees (82%) within 80 km.

3 km
393 m
16 km
2,103 m
80 km
3,141 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Miyota 7.0 km · Tōmi 8.0 km · Saku 12 km · Kamimaruko 14 km · Ueda 17 km · Karuizawa 18 km · Sakaki 28 km · Suzaka 38 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 Komoro (36.3167°, 138.4333°, elevation 686 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).