Ryōtsu-minato weather in September

In September, Ryōtsu-minato sees average daytime highs of 25°C and overnight lows near 21°C, with 142 mm of rain across 12.5 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 22°C by the end. The sky is clear or mostly clear about 26% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Ryōtsu-minato's 6th-clearest and 8th-windiest month. For the whole year in context, see Ryōtsu-minato's year-round climate.

Daytime high
25°
3rd warmest
Overnight low
21°
10th coldest
Rainfall
142 mm
12.5 wet days
Daylight
12 h 12 min
5:33 AM – 5:48 PM
Cloud cover
64%
6th clearest
Wind
12 km/h
8th windiest
Solar energy
4.13 kWh/m²
Travel score
6.2
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 27°C in the first days to 22°C by the end.

A typical September day in Ryōtsu-minato reaches about 25°C in the afternoon and slips back to 21°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 28°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12723
22723
32723
42723
52723
62623
72622
82622
92622
102622
112622
122522
132521
142521
152521
162521
172521
182421
192420
202420
212420
222420
232320
242319
252319
262319
272319
282219
292219
302218

How September really feels in Ryōtsu-minato

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.

Ryōtsu-minato weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 13221.49.89.70.2
Feb / 9117.68.210.50.3
Mar / 10116.23.311.71.4
Apr13° / 8912.20.2133.5
May18° / 13°92110145.8
Jun22° / 18°12410.5014.66.4
Jul26° / 22°20514.3014.45.8
Aug28° / 24°14612.1013.55.6
Sep25° / 21°14212.5012.36.2
Oct19° / 15°13613.20115.7
Nov14° / 10°13717.30.19.93.3
Dec / 15421.64.89.41.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% 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 58%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14555
24555
34357
44456
54456
64456
74456
84456
94555
104456
114456
124357
134357
144357
154357
164258
174159
184159
194159
204159
214060
224060
234060
244060
254159
264159
274159
284159
294159
304258

Chance of precipitation in September

Any precipitation

Ryōtsu-minato gets around 142 mm of rain over 12.5 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 43% and peaks near 45% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
144
245
345
445
545
645
745
845
945
1045
1145
1244
1344
1444
1543
1643
1742
1842
1941
2041
2140
2240
2340
2440
2540
2640
2740
2840
2940
3041

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 28% of days. Sticky, muggy-or-worse air turns up on roughly 47% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1031637395
2031737384
3041837364
4042037354
5152137343
6152337323
7162436312
8172536292
9282635272
10292735262
113102734241
123122833221
134132832211
145142931191
156163030181
167173029160
179183128140
1810203127130
1911213125110
2013223124100
211423312380
221624312270
231725322060
241926321950
252027321840
262228311630
272329311520
282530311320
292630301210
302831291110

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1012calm
1112calm
1212calm
1312calm
1412calm
1512calm
1612calm
1712light breeze
1812light breeze
1912light breeze
2012light breeze
2112light breeze
2212light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 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 72 minutes over September. Sunrise moves from 5:20 AM to 5:46 AM, and sunset from 6:12 PM to 5:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:206:12
212.85:216:10
312.85:226:09
412.75:236:07
512.75:246:06
612.75:246:04
712.65:256:02
812.65:266:01
912.55:275:59
1012.55:285:58
1112.55:295:56
1212.45:305:54
1312.45:315:53
1412.35:325:51
1512.35:325:49
1612.25:335:48
1712.25:345:46
1812.25:355:45
1912.15:365:43
2012.15:375:41
2112.05:385:40
2212.05:395:38
2311.95:405:36
2411.95:405:35
2511.95:415:33
2611.85:425:32
2711.85:435:30
2811.75:445:28
2911.75:455:27
3011.75:465:25

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.13 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 5.85 kWh/m² in May across the year — September's 4.13 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.6Bright
34.6Bright
44.5Bright
54.5Bright
64.5Bright
74.4Bright
84.4Bright
94.3Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.1Bright
154.1Bright
164.1Bright
174.0Bright
184.0Bright
194.0Moderate
204.0Moderate
213.9Moderate
223.9Moderate
233.9Moderate
243.9Moderate
253.8Moderate
263.8Moderate
273.8Moderate
283.8Moderate
293.7Moderate
303.7Moderate
Planning a trip in September

Hazard calendar for Ryōtsu-minato

In seasonPeak

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

Ryōtsu-minato 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 Ryōtsu-minato?

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

6.2
Sightseeing
2nd-best month of the year
5.4
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Ryōtsu-minato for sightseeing.

What to pack for Ryōtsu-minato in September

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

In September, Ryōtsu-minato sees daytime highs around 25°C and nights near 21°C. Worth packing: light clothes and rain gear. About 13 days see rain.

light clothesrain gear

Sea temperature near Ryōtsu-minato 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 March near 10°C.

It's comfortable for a long swim from Jun 24 to Oct 29 — about 4.2 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb10Bracing
Mar10Bracing
Apr11Bracing
May14Bracing
Jun19Cool
Jul23Refreshing
Aug26Warm
Sep25Warm
Oct22Refreshing
Nov18Cool
Dec15Cool

UV index in Ryōtsu-minato in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Ryōtsu-minato peaks around August 14 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateAug 14UV 9Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun8Very high
Jul9Very high
Aug10Very high
Sep8Very high
Oct5Moderate
Nov3Moderate
Dec2Low

Air quality in Ryōtsu-minato 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 Ryōtsu-minato is worst in April — around 20 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1220 µg/m³Oct 129 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar20Moderate
Apr20Moderate
May18Moderate
Jun14Moderate
Jul12Moderate
Aug10Good
Sep9Good
Oct9Good
Nov10Good
Dec9Good
Location & terrain

Where is Ryōtsu-minato?

Ryōtsu-minato sits at 38.1°N, 138.4°E, 4 m above sea level, in Japan. The nearest listed city is Sado, 9.0 km away.

Topography around Ryōtsu-minato

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

Within 3 km, the terrain around Ryōtsu-minato has only modest variations in elevation — a maximum elevation change of 102 m around an average of 11 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,155 m; within 80 km, large variations in elevation — a maximum elevation change of 1,125 m.

The land around Ryōtsu-minato is covered by water (50%) and trees (23%) within 3 km, trees (55%) and water (34%) within 16 km, and water (78%) within 80 km.

3 km
102 m
16 km
1,155 m
80 km
1,125 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Sado 9.0 km · Maki 53 km · Niigata 55 km · Yoshida-kasugachō 59 km · Shirone 62 km · Tsubame 63 km · Kameda-honchō 63 km · Niitsu-honchō 67 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 Ryōtsu-minato (38.0782°, 138.4394°, elevation 4 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).