Imaichi weather in September

In September, Imaichi sees average daytime highs of 23°C and overnight lows near 17°C, with 290 mm of rain across 20.3 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 25°C in the first days to 21°C by the end. The sky is clear or mostly clear about 13% 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 Imaichi's 9th-clearest and 9th-windiest month. For the whole year in context, see Imaichi's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
17°
10th coldest
Rainfall
290 mm
20.3 wet days
Daylight
12 h 12 min
5:29 AM – 5:43 PM
Cloud cover
73%
9th clearest
Wind
5 km/h
9th windiest
Solar energy
3.55 kWh/m²
Travel score
4.9
out of 10

Imaichi is human settlement in Japan.

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 21°C by the end.

A typical September day in Imaichi reaches about 23°C in the afternoon and slips back to 17°C overnight — a 6°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 5°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12519
22519
32519
42519
52519
62519
72518
82518
92418
102418
112418
122418
132417
142417
152317
162317
172317
182316
192316
202216
212216
222215
232215
242215
252115
262115
272114
282114
292114
302114

How September really feels in Imaichi

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.

Imaichi 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°618.58.39.80.0
Feb / -3°598.97.110.60.1
Mar / -0°12214.27.611.71.5
Apr14° / 15215.12.112.93.7
May19° / 10°19717.40.113.95.0
Jun22° / 15°25521.8014.54.5
Jul26° / 19°34325.8014.34.2
Aug27° / 20°28523.9013.44.4
Sep23° / 17°29020.3012.24.9
Oct18° / 10°22017.50.111.14.7
Nov12° / 95100.4103.3
Dec / -1°6195.19.50.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% 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 71%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12971
22971
32971
43070
53070
63070
72971
82971
92971
102872
112773
122872
132872
142773
152773
162872
172872
182872
192872
202773
212872
222971
233070
243070
253169
263169
273268
283367
293367
303367

Chance of precipitation in September

Any precipitation

Imaichi gets around 290 mm of rain over 20.3 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 69% and peaks near 73% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
173
272
372
472
572
671
771
871
971
1071
1171
1271
1371
1470
1570
1670
1769
1869
1968
2067
2167
2266
2365
2465
2564
2664
2764
2864
2964
3064

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 32% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
117304913
218314813
318324812
419334711
529334510
6210344410
731134439
831334428
941435407
1051535387
1161734376
1271834356
1392034335
14102133314
15122333294
16132532273
17152731253
18172830232
19193029212
20213128192
21233227171
22253325151
23273424131
24293523121
25313622101
2633372180
2735382070
2836391960
2938391850
3040391740

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 5:16 AM to 5:40 AM, and sunset from 6:06 PM to 5:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:166:06
212.85:176:04
312.75:186:03
412.75:196:01
512.75:206:00
612.65:205:58
712.65:215:57
812.55:225:55
912.55:235:53
1012.55:245:52
1112.45:255:50
1212.45:255:49
1312.45:265:47
1412.35:275:46
1512.35:285:44
1612.25:295:43
1712.25:305:41
1812.25:305:39
1912.15:315:38
2012.15:325:36
2112.05:335:35
2212.05:345:33
2311.95:355:32
2411.95:355:30
2511.95:365:28
2611.85:375:27
2711.85:385:25
2811.75:395:24
2911.75:405:22
3011.75:405:21

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.55 kWh/m².

For context, solar energy here swings from a low near 2.29 kWh/m² to a high of 5.18 kWh/m² in May across the year — September's 3.55 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.9Moderate
23.9Moderate
33.9Moderate
43.9Moderate
53.8Moderate
63.8Moderate
73.8Moderate
83.7Moderate
93.7Moderate
103.7Moderate
113.6Moderate
123.6Moderate
133.6Moderate
143.6Moderate
153.5Moderate
163.5Moderate
173.5Moderate
183.5Moderate
193.4Moderate
203.4Moderate
213.4Moderate
223.4Moderate
233.3Moderate
243.3Moderate
253.3Moderate
263.3Moderate
273.2Moderate
283.2Moderate
293.2Moderate
303.2Moderate
Planning a trip in September

Hazard calendar for Imaichi

In seasonPeak

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

Imaichi's rainy season runs May–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 Imaichi?

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

4.9
Sightseeing
2nd-best month of the year
3.8
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Imaichi for sightseeing.

What to pack for Imaichi in September

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

In September, Imaichi sees daytime highs around 23°C and nights near 17°C. Pack rain gear. Worth having: light clothes. About 20 days see rain.

rain gearlight clothes

UV index in Imaichi 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 Imaichi peaks around July 18 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 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 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5High
Apr7High
May9Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep9Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Imaichi 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 Imaichi is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1721 µg/m³Dec 179 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun16Moderate
Jul14Moderate
Aug13Moderate
Sep11Good
Oct11Good
Nov10Good
Dec9Good
Location & terrain

Where is Imaichi?

Imaichi sits at 36.7°N, 139.7°E, 391 m above sea level, in Japan. The nearest listed city is Nikko, 7.0 km away.

Topography around Imaichi

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

Within 3 km, the terrain around Imaichi has significant variations in elevation — a maximum elevation change of 342 m around an average of 421 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,085 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,551 m.

The land around Imaichi is covered by trees (61%) within 3 km, trees (82%) within 16 km, and trees (70%) within 80 km.

3 km
342 m
16 km
2,085 m
80 km
2,551 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Nikko 7.0 km · Kanuma 19 km · Yaita 24 km · Utsunomiya 24 km · Ujiie 26 km · Sakura 27 km · Hōshakuji 28 km · Mibu 35 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 Imaichi (36.7167°, 139.6833°, elevation 391 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).