Yōkaichiba weather in September

In September, Yōkaichiba sees average daytime highs of 26°C and overnight lows near 22°C, with 168 mm of rain across 14 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 28°C in the first days to 24°C by the end. The sky is clear or mostly clear about 23% 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 Yōkaichiba's 9th-clearest and 7th-windiest month. For the whole year in context, see Yōkaichiba's year-round climate.

Daytime high
26°
3rd warmest
Overnight low
22°
10th coldest
Rainfall
168 mm
14 wet days
Daylight
12 h 12 min
5:25 AM – 5:39 PM
Cloud cover
66%
9th clearest
Wind
14 km/h
7th windiest
Solar energy
4.11 kWh/m²
Travel score
5.8
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 28°C in the first days to 24°C by the end.

A typical September day in Yōkaichiba reaches about 26°C in the afternoon and slips back to 22°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 30°C. Set against its neighbours, September runs about 3°C cooler than August and about 5°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12824
22824
32823
42823
52823
62823
72823
82823
92723
102723
112723
122722
132722
142722
152622
162622
172621
182621
192621
202521
212521
222521
232520
242520
252520
262420
272420
282420
292419
302419

How September really feels in Yōkaichiba

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.

Yōkaichiba 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 / 828.70.79.92.1
Feb10° / 7790.810.62.3
Mar13° / 13013.10.511.73.4
Apr17° / 11°11212.6012.95.2
May21° / 16°12811.7013.96.1
Jun24° / 19°15913.2014.45.9
Jul28° / 23°14213.3014.25.4
Aug29° / 24°10111.1013.35.1
Sep26° / 22°16814012.25.8
Oct21° / 17°20913.2011.16.1
Nov17° / 11°10910.9010.15.2
Dec12° / 779.409.63.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 23% 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 61%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14258
24258
34258
44258
54258
64258
74258
84159
94159
104159
114159
124159
134159
144060
153961
163961
173961
183862
193862
203664
213664
223565
233664
243565
253565
263565
273565
283565
293664
303664

Chance of precipitation in September

Any precipitation

Yōkaichiba gets around 168 mm of rain over 14 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 47% and peaks near 48% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
144
245
345
446
546
647
747
847
947
1048
1148
1248
1348
1448
1548
1648
1748
1848
1948
2048
2147
2247
2347
2447
2547
2647
2747
2846
2946
3046

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 33% of days. Sticky, muggy-or-worse air turns up on roughly 70% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1016245316
2016245316
3016255315
4017265214
5018275014
6018275113
7029284812
80210294712
90311294611
100312304510
111413304310
12141430429
13151531408
14161631387
15271731367
16281832346
17291932325
183102132305
194112232284
204122332263
215132432243
225142532222
236152532202
247162731182
258162831161
268172931141
279173031121
2810183130111
291118312991
301218322980

Wind in September

Winds average 14 km/h in September.

Across September, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze

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 5:14 AM to 5:37 AM, and sunset from 6:01 PM to 5:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:146:01
212.85:156:00
312.75:155:58
412.75:165:57
512.65:175:55
612.65:185:54
712.65:185:52
812.55:195:51
912.55:205:49
1012.55:215:48
1112.45:225:46
1212.45:225:45
1312.35:235:43
1412.35:245:42
1512.35:255:40
1612.25:255:39
1712.25:265:37
1812.15:275:36
1912.15:285:34
2012.15:295:33
2112.05:295:31
2212.05:305:30
2312.05:315:28
2411.95:325:27
2511.95:335:25
2611.85:335:24
2711.85:345:22
2811.85:355:21
2911.75:365:19
3011.75:375:18

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.11 kWh/m².

For context, solar energy here swings from a low near 2.31 kWh/m² to a high of 5.44 kWh/m² in May across the year — September's 4.11 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Moderate
193.9Moderate
203.9Moderate
213.8Moderate
223.8Moderate
233.7Moderate
243.7Moderate
253.6Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Yōkaichiba

In seasonPeak

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

Yōkaichiba 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 Yōkaichiba?

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

5.8
Sightseeing
4th-best month of the year
5.7
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Yōkaichiba for sightseeing.

What to pack for Yōkaichiba in September

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

In September, Yōkaichiba sees daytime highs around 26°C and nights near 22°C. Pack rain gear. Worth having: light clothes. About 14 days see rain.

rain gearlight clothes

Sea temperature near Yōkaichiba 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 25°C and coldest in February near 15°C.

It's comfortable for a long swim from Jun 5 to Nov 22 — about 5.6 months when the water holds above 20°C.

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Bracing
Mar15Cool
Apr16Cool
May19Cool
Jun21Refreshing
Jul23Refreshing
Aug25Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Yōkaichiba 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 Yōkaichiba peaks around August 12 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 highVery highModerateAug 12UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar4Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec2Moderate

Air quality in Yōkaichiba 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 Yōkaichiba is worst in March — around 25 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (December, 14 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2425 µg/m³Dec 1914 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb18Moderate
Mar25Moderate
Apr25Moderate
May24Moderate
Jun19Moderate
Jul16Moderate
Aug15Moderate
Sep15Moderate
Oct16Moderate
Nov16Moderate
Dec14Moderate
Location & terrain

Where is Yōkaichiba?

Yōkaichiba sits at 35.7°N, 140.6°E, 10 m above sea level, in Japan. The nearest listed city is Sōsa, 2.0 km away.

Topography around Yōkaichiba

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

Within 3 km, the terrain around Yōkaichiba has only modest variations in elevation — a maximum elevation change of 53 m around an average of 17 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 72 m; within 80 km, large variations in elevation — a maximum elevation change of 840 m.

The land around Yōkaichiba is covered by trees (39%), cropland (37%) and artificial surfaces (20%) within 3 km, cropland (31%), trees (30%) and water (22%) within 16 km, and water (42%) and trees (24%) within 80 km.

3 km
53 m
16 km
72 m
80 km
840 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Sōsa 2.0 km · Yokoshiba 8.0 km · Asahi 9.0 km · Sanmu 14 km · Narutō 16 km · Ryōgoku 17 km · Omigawa 18 km · Sawara 21 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 Yōkaichiba (35.7°, 140.55°, elevation 10 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).