Chikuma weather in September

In September, Chikuma sees average daytime highs of 23°C and overnight lows near 14°C, with 256 mm of rain across 19 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 16% 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 Chikuma's 10th-clearest and 9th-windiest month. For the whole year in context, see Chikuma's year-round climate.

Daytime high
23°
3rd warmest
Overnight low
14°
10th coldest
Rainfall
256 mm
19 wet days
Daylight
12 h 12 min
5:35 AM – 5:49 PM
Cloud cover
71%
10th clearest
Wind
5 km/h
9th windiest
Solar energy
3.97 kWh/m²
Travel score
5.1
out of 10

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 Chikuma reaches about 23°C in the afternoon and slips back to 14°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 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
52517
62416
72416
82416
92416
102416
112416
122315
132315
142315
152315
162315
172214
182214
192214
202214
212113
222113
232113
242113
252112
262012
272012
282012
292012
302011

How September really feels in Chikuma

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.

Chikuma 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 / -7°15220.121.79.80.0
Feb / -6°12916.716.910.60.0
Mar / -3°18017.814.111.70.5
Apr13° / 15815.53.912.93.1
May19° / 19316.40.113.95.1
Jun22° / 14°28820.6014.44.7
Jul25° / 18°33823.2014.24.6
Aug27° / 18°22519.7013.45.1
Sep23° / 14°25619012.25.1
Oct17° / 22318.50.211.14.3
Nov10° / 14916.85.310.12.1
Dec / -4°15519.717.39.60.1

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 17% of September, with mostly cloudy or overcast conditions the remaining 67%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13466
23466
33565
43565
53565
63565
73466
83466
93466
103367
113367
123466
133367
143268
153268
163367
173169
183169
193169
203169
213169
223169
233169
243169
253169
263169
273268
283268
293268
303268

Chance of precipitation in September

Any precipitation

Chikuma gets around 256 mm of rain over 19 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 64% and peaks near 67% on the wettest days.

0%20%40%60%80%151015202530
Rain chance (%)
167
267
367
467
567
667
766
866
966
1066
1165
1265
1364
1464
1564
1663
1763
1863
1963
2062
2162
2262
2362
2462
2562
2662
2763
2863
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 34% of days. Sticky, muggy-or-worse air turns up on roughly 8% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
152051231
252152220
362153200
472252190
582351180
682451170
792551150
8112749140
9122847130
10132946120
11153045110
1217314390
1319314280
1421324070
1523333760
1626333560
1729343350
1831343040
1934342830
2037342630
2140342320
2243332120
2346331910
2449321710
2552321510
2655311310
2757301210
2861291000
296328900
306527800

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 5:23 AM to 5:47 AM, and sunset from 6:12 PM to 5:27 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:236:12
212.85:246:10
312.75:246:09
412.75:256:07
512.75:266:06
612.65:276:04
712.65:286:03
812.55:296:01
912.55:296:00
1012.55:305:58
1112.45:315:57
1212.45:325:55
1312.35:335:54
1412.35:335:52
1512.35:345:50
1612.25:355:49
1712.25:365:47
1812.15:375:46
1912.15:385:44
2012.15:385:43
2112.05:395:41
2212.05:405:39
2312.05:415:38
2411.95:425:36
2511.95:435:35
2611.85:435:33
2711.85:445:32
2811.85:455:30
2911.75:465:29
3011.75:475:27

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.97 kWh/m².

For context, solar energy here swings from a low near 2.27 kWh/m² to a high of 5.7 kWh/m² in May across the year — September's 3.97 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.3Bright
54.3Bright
64.3Bright
74.2Bright
84.2Bright
94.1Bright
104.1Bright
114.1Bright
124.0Bright
134.0Bright
144.0Moderate
154.0Moderate
163.9Moderate
173.9Moderate
183.9Moderate
193.8Moderate
203.8Moderate
213.8Moderate
223.8Moderate
233.7Moderate
243.7Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.6Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Chikuma?

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

5.1
Sightseeing
1st-best month of the year
3.7
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Chikuma for sightseeing.

What to pack for Chikuma in September

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

In September, Chikuma sees daytime highs around 23°C and nights near 14°C. Pack rain gear. Worth having: light clothes. About 19 days see rain.

rain gearlight clothes

Sea temperature near Chikuma in September

The nearest coast averages about 25°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 67 km away) is warmest in August at about 27°C and coldest in March near 10°C.

It's comfortable for a long swim from Jun 20 to Nov 1 — about 4.4 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb11Bracing
Mar10Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug27Warm
Sep25Warm
Oct22Refreshing
Nov19Cool
Dec15Cool

UV index in Chikuma 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 Chikuma peaks around July 20 at about 10 (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 20UV 10Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Very high
Jul10Extreme
Aug10Extreme
Sep9Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Chikuma 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 Chikuma 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 1721 µg/m³Dec 1510 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar20Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug13Moderate
Sep12Good
Oct11Good
Nov11Good
Dec10Good
Location & terrain

Where is Chikuma?

Chikuma sits at 36.5°N, 138.1°E, 388 m above sea level, in Japan. The nearest listed city is Sakaki, 11 km away.

Topography around Chikuma

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

Within 3 km, the terrain around Chikuma has large variations in elevation — a maximum elevation change of 635 m around an average of 539 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,102 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,130 m.

The land around Chikuma is covered by trees (54%) and artificial surfaces (22%) within 3 km, trees (78%) within 16 km, and trees (78%) within 80 km.

3 km
635 m
16 km
1,102 m
80 km
3,130 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Sakaki 11 km · Nagano 16 km · Ōmachi 20 km · Ueda 22 km · Suzaka 24 km · Hotaka 28 km · Kamimaruko 28 km · Toyoshina 30 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 Chikuma (36.5271°, 138.0894°, elevation 388 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. 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).