Minamibōsō weather in September

In September, Minamibōsō sees average daytime highs of 25°C and overnight lows near 23°C, with 211 mm of rain across 14.6 wet days and about 12.2 hours of daylight. It is the 2nd-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 26°C in the first days to 23°C by the end. The sky is clear or mostly clear about 30% of the time in September, and the air most often feels oppressive.

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

Daytime high
25°
2nd warmest
Overnight low
23°
10th coldest
Rainfall
211 mm
14.6 wet days
Daylight
12 h 12 min
5:28 AM – 5:41 PM
Cloud cover
62%
9th clearest
Wind
21 km/h
9th windiest
Solar energy
4.15 kWh/m²
Travel score
6.0
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 26°C in the first days to 23°C by the end.

A typical September day in Minamibōsō reaches about 25°C in the afternoon and slips back to 23°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 27°C. Set against its neighbours, September runs about 2°C cooler than August and about 4°C warmer than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12624
22624
32624
42624
52624
62624
72624
82624
92624
102623
112623
122523
132523
142523
152523
162523
172523
182522
192522
202422
212422
222422
232422
242422
252421
262421
272421
282321
292321
302321

Minamibōsō weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan11° / 104109.92.6
Feb11° / 10410.710.72.5
Mar13° / 17614.911.73.3
Apr16° / 13°14312.112.94.8
May19° / 17°15811.513.85.9
Jun22° / 20°22013.714.35.7
Jul25° / 23°14911.514.16.5
Aug26° / 25°1039.513.36.7
Sep25° / 23°21114.612.26.0
Oct21° / 18°25314.511.15.9
Nov17° / 14°16013.410.25.2
Dec13° / 103119.73.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 55%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35149
45149
55149
65149
75050
85050
94852
104852
114852
124852
134753
144753
154555
164555
174456
184456
194159
204159
214060
224060
233961
243961
253961
263961
273961
283961
293961
303961

Chance of precipitation in September

Any precipitation

Minamibōsō gets around 211 mm of rain over 14.6 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 49% and peaks near 51% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
143
243
344
445
546
647
747
848
949
1049
1150
1250
1350
1450
1550
1650
1750
1850
1950
2050
2150
2250
2350
2450
2550
2650
2750
2850
2951
3051

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 36% of days. Sticky, muggy-or-worse air turns up on roughly 77% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1004184830
2004194829
3004204828
4004214727
5015224726
6015234724
7016244623
8017254621
9017264520
10028274518
11029274417
120310284415
131311294314
141412304212
151513304011
16161431399
17171531388
18281632367
19291732346
202101833325
213112033304
223112133283
234122233263
244132334242
254142434222
265142534201
275152634191
286162634171
296162734151
307172834141

Wind in September

Winds average 21 km/h in September.

Across September, daily wind ranges from about 19 km/h on the calmest days to 23 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
119light breeze
219light breeze
319light breeze
419light breeze
519light breeze
620light breeze
720light breeze
820light breeze
920light breeze
1020light breeze
1120breezy
1220breezy
1320breezy
1421breezy
1521breezy
1621breezy
1721breezy
1821breezy
1921breezy
2022breezy
2122breezy
2222breezy
2322breezy
2422breezy
2522breezy
2622breezy
2722breezy
2822breezy
2923breezy
3023breezy

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 5:17 AM to 5:39 AM, and sunset from 6:03 PM to 5:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:176:03
212.75:186:02
312.75:186:00
412.75:195:59
512.65:205:57
612.65:215:56
712.65:215:55
812.55:225:53
912.55:235:52
1012.45:245:50
1112.45:245:49
1212.45:255:47
1312.35:265:46
1412.35:275:44
1512.35:275:43
1612.25:285:41
1712.25:295:40
1812.15:305:38
1912.15:305:37
2012.15:315:35
2112.05:325:34
2212.05:335:32
2312.05:335:31
2411.95:345:29
2511.95:355:28
2611.85:365:26
2711.85:375:25
2811.85:375:23
2911.75:385:22
3011.75:395:20

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.15 kWh/m².

For context, solar energy here swings from a low near 2.29 kWh/m² to a high of 5.49 kWh/m² in August across the year — September's 4.15 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.7Bright
54.7Bright
64.7Bright
74.6Bright
84.5Bright
94.5Bright
104.5Bright
114.4Bright
124.3Bright
134.3Bright
144.2Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.7Moderate
253.7Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Minamibōsō

In seasonPeak

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

Minamibōsō sits in the Pacific typhoon belt; the season peaks July–October.

Pacific typhoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Minamibōsō?

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

6.0
Sightseeing
3rd-best month of the year
5.4
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Minamibōsō for sightseeing.

What to pack for Minamibōsō in September

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

In September, Minamibōsō sees daytime highs around 25°C and nights near 23°C. Pack rain gear. Worth having: light clothes and a windbreaker. About 15 days see rain.

rain gearlight clothesa windbreaker

Sea temperature near Minamibōsō 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 offshore is warmest in August at about 26°C and coldest in February near 15°C.

It's comfortable for a long swim from May 31 to Nov 24 — about 5.9 months when the water holds above 20°C.

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Cool
Mar15Cool
Apr17Cool
May19Cool
Jun21Refreshing
Jul24Refreshing
Aug26Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Minamibōsō in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Minamibōsō peaks around August 10 at about 10 (extreme) — 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 highExtremeVery highHighModerateAug 10UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug10Extreme
Sep8Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Minamibōsō 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 Minamibōsō is worst in April — around 22 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (September, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateApr 1322 µg/m³Sep 911 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb17Moderate
Mar21Moderate
Apr22Moderate
May21Moderate
Jun16Moderate
Jul12Good
Aug11Good
Sep11Good
Oct14Moderate
Nov14Moderate
Dec13Moderate
Location & terrain

Where is Minamibōsō?

Minamibōsō sits at 35.0°N, 139.9°E, 66 m above sea level, in Japan. The nearest listed city is Tateyama, 8.0 km away.

Topography around Minamibōsō

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

Within 3 km, the terrain around Minamibōsō has only modest variations in elevation — a maximum elevation change of 242 m around an average of 61 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 404 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,220 m.

The land around Minamibōsō is covered by trees (68%) and cropland (23%) within 3 km, trees (49%) and water (40%) within 16 km, and water (64%) within 80 km.

3 km
242 m
16 km
404 m
80 km
1,220 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Tateyama 8.0 km · Kamogawa 17 km · Kurihama 30 km · Miura 30 km · Futtsu 33 km · Kimitsu 36 km · Yokosuka 37 km · Katsuura 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 Minamibōsō (35.0313°, 139.9265°, elevation 66 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).