Numata weather in September

In September, Numata sees average daytime highs of 21°C and overnight lows near 15°C, with 176 mm of rain across 15.8 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 24°C in the first days to 19°C by the end. The sky is clear or mostly clear about 17% of the time in September, and the air most often feels comfortable.

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 Numata's 10th-clearest and 9th-windiest month. For the whole year in context, see Numata's year-round climate.

Daytime high
21°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
176 mm
15.8 wet days
Daylight
12 h 12 min
5:31 AM – 5:45 PM
Cloud cover
71%
10th clearest
Wind
5 km/h
9th windiest
Solar energy
3.78 kWh/m²
Travel score
5.4
out of 10

Numata is city in Gunma prefecture, Japan.

Density
106/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 24°C in the first days to 19°C by the end.

A typical September day in Numata reaches about 21°C in the afternoon and slips back to 15°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 17°C and 25°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)
12417
22417
32417
42317
52317
62317
72316
82316
92316
102316
112216
122216
132215
142215
152215
162115
172114
182114
192114
202114
212014
222013
232013
242013
251913
261912
271912
281912
291912
301912

How September really feels in Numata

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.

Numata 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 / -6°11020.621.89.80.0
Feb / -6°9417.418.410.60.0
Mar / -3°12317.914.811.70.3
Apr12° / 11614.94.212.92.7
May17° / 12914.90.313.94.9
Jun21° / 13°15517.1014.55.0
Jul24° / 18°20520.4014.25.0
Aug25° / 18°14517.1013.45.6
Sep21° / 15°17615.8012.25.4
Oct16° / 15313.70.311.14.4
Nov10° / 8513.44.8102.0
Dec / -3°9618.216.69.50.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 17% 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 67%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13565
23466
33466
43466
53466
63367
73367
83367
93367
103268
113367
123367
133268
143268
153268
163268
173367
183367
193367
203367
213367
223367
233466
243466
253466
263466
273466
283466
293466
303565

Chance of precipitation in September

Any precipitation

Numata gets around 176 mm of rain over 15.8 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 54% and peaks near 57% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
157
257
356
456
556
656
756
856
955
1055
1155
1255
1355
1455
1555
1654
1754
1854
1953
2053
2152
2252
2352
2451
2551
2650
2750
2850
2949
3049

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels comfortable — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the comfortable band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 13% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
142044311
242144301
352244281
462344271
562444261
672543240
782643230
8102742210
9112841200
10122940180
11143039170
12163137160
13183236140
14203334130
15223333120
16253431100
1728342990
1830352780
1933352570
2036352360
2139342150
2242341940
2345341740
2449331530
2551321430
2655311220
2758301020
286129910
296328810
306527710

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 6 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
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 5:19 AM to 5:43 AM, and sunset from 6:08 PM to 5:23 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:196:08
212.85:206:07
312.75:216:05
412.75:216:04
512.75:226:02
612.65:236:01
712.65:245:59
812.55:255:57
912.55:255:56
1012.55:265:54
1112.45:275:53
1212.45:285:51
1312.35:295:50
1412.35:305:48
1512.35:305:47
1612.25:315:45
1712.25:325:43
1812.15:335:42
1912.15:345:40
2012.15:355:39
2112.05:355:37
2212.05:365:36
2311.95:375:34
2411.95:385:32
2511.95:395:31
2611.85:405:29
2711.85:405:28
2811.85:415:26
2911.75:425:25
3011.75:435:23

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.78 kWh/m².

For context, solar energy here swings from a low near 2.2 kWh/m² to a high of 5.51 kWh/m² in May across the year — September's 3.78 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.2Bright
24.2Bright
34.2Bright
44.1Bright
54.1Bright
64.0Bright
74.0Bright
84.0Moderate
93.9Moderate
103.9Moderate
113.9Moderate
123.8Moderate
133.8Moderate
143.8Moderate
153.8Moderate
163.7Moderate
173.7Moderate
183.7Moderate
193.6Moderate
203.6Moderate
213.6Moderate
223.5Moderate
233.5Moderate
243.5Moderate
253.5Moderate
263.5Moderate
273.4Moderate
283.4Moderate
293.4Moderate
303.4Moderate
Planning a trip in September

Is September a good time to visit Numata?

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

5.4
Sightseeing
2nd-best month of the year
3.5
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Numata for sightseeing.

What to pack for Numata in September

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

In September, Numata sees daytime highs around 21°C and nights near 15°C. Pack rain gear. About 16 days see rain.

rain gear

UV index in Numata 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 Numata peaks around July 24 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 24UV 10Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5High
Apr7Very high
May9Very high
Jun9Very high
Jul10Very high
Aug10Very high
Sep9Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Numata 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 Numata is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 1610 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug13Moderate
Sep12Good
Oct12Good
Nov11Good
Dec10Good
Location & terrain

Where is Numata?

Numata sits at 36.6°N, 139.1°E, 376 m above sea level, in Japan. The nearest listed city is Minakami, 8.0 km away.

Topography around Numata

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

Within 3 km, the terrain around Numata has significant variations in elevation — a maximum elevation change of 266 m around an average of 400 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,659 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,544 m.

The land around Numata is covered by artificial surfaces (35%), trees (32%) and cropland (28%) within 3 km, trees (78%) within 16 km, and trees (77%) within 80 km.

3 km
266 m
16 km
1,659 m
80 km
2,544 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Minakami 8.0 km · Shibukawa 17 km · Nakanojō 19 km · Ogura 20 km · Kanekomachi 25 km · Maebashi 26 km · Midori 30 km · Ōmamachō-ōmama 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 Numata (36.6333°, 139.05°, elevation 376 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).