Sukumo weather in September

In September, Sukumo sees average daytime highs of 28°C and overnight lows near 22°C, with 239 mm of rain across 14.9 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 29°C in the first days to 26°C by the end. The sky is clear or mostly clear about 32% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Sukumo's 9th-clearest and 10th-windiest month. For the whole year in context, see Sukumo's year-round climate.

Daytime high
28°
3rd warmest
Overnight low
22°
10th coldest
Rainfall
239 mm
14.9 wet days
Daylight
12 h 12 min
5:57 AM – 6:09 PM
Cloud cover
61%
9th clearest
Wind
11 km/h
10th windiest
Solar energy
4.28 kWh/m²
Travel score
5.4
out of 10

Sukumo is city in Kōchi Prefecture, Japan.

Density
67/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 29°C in the first days to 26°C by the end.

A typical September day in Sukumo reaches about 28°C in the afternoon and slips back to 22°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 30°C. Set against its neighbours, September runs about 3°C cooler than August and about 4°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12924
22924
32924
42923
52923
62923
72923
82923
92823
102823
112823
122823
132822
142822
152822
162822
172722
182722
192721
202721
212721
222721
232721
242721
252621
262620
272620
282620
292620
302620

How September really feels in Sukumo

Once humidity and wind are folded in, September averages 4 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
4
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Sukumo 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 daysDaylight (hours)Travel score
Jan11° / 666.310.12.8
Feb12° / 848.210.83.1
Mar15° / 13611.311.74.4
Apr19° / 12°1601112.86.0
May23° / 16°1891213.76.4
Jun25° / 20°32816.614.15.4
Jul29° / 24°25215.8144.6
Aug30° / 25°19215.413.24.4
Sep28° / 22°23914.912.25.4
Oct23° / 17°18310.111.27.0
Nov18° / 12°1088.710.36.1
Dec13° / 806.79.94.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14357
24357
34357
44258
54357
64357
74357
84357
94456
104456
114456
124555
134555
144654
154654
164654
174654
184654
194753
204753
214753
224852
234852
244852
254852
264951
274951
284852
294951
304951

Chance of precipitation in September

Any precipitation

Sukumo gets around 239 mm of rain over 14.9 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 50% and peaks near 56% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
156
256
355
455
555
655
755
854
954
1054
1153
1253
1352
1451
1550
1649
1749
1848
1947
2047
2146
2245
2345
2444
2544
2643
2743
2843
2943
3043

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 72% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1004195225
2005205223
3005215222
4006225220
5016235119
6017245117
7017255116
8018264915
9029274814
101210274713
111311284512
121413284311
131414294110
14251529409
15261729389
16271829368
17382029347
18382128327
19492228316
204102428296
215112528275
225122627255
235122727244
246132827224
256142927214
266152927203
277163027183
287173026172
298183026162
308183026152

Wind in September

Winds average 11 km/h in September.

Across September, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 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 60 minutes over September. Sunrise moves from 5:47 AM to 6:07 AM, and sunset from 6:30 PM to 5:50 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:476:30
212.75:486:29
312.65:496:27
412.65:496:26
512.65:506:25
612.55:516:23
712.55:516:22
812.55:526:21
912.45:536:19
1012.45:536:18
1112.45:546:16
1212.35:556:15
1312.35:556:14
1412.35:566:12
1512.25:576:11
1612.25:576:09
1712.25:586:08
1812.15:596:07
1912.15:596:05
2012.16:006:04
2112.06:016:02
2212.06:016:01
2312.06:026:00
2411.96:035:58
2511.96:035:57
2611.96:045:55
2711.86:055:54
2811.86:065:53
2911.76:065:51
3011.76:075:50

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.28 kWh/m².

For context, solar energy here swings from a low near 2.56 kWh/m² to a high of 5.46 kWh/m² in May across the year — September's 4.28 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.7Bright
54.6Bright
64.6Bright
74.6Bright
84.5Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.4Bright
144.4Bright
154.3Bright
164.3Bright
174.3Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.1Bright
234.1Bright
244.1Bright
254.0Bright
264.0Bright
274.0Moderate
284.0Moderate
293.9Moderate
303.9Moderate
Planning a trip in September

Hazard calendar for Sukumo

In seasonPeak

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

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

Sukumo's rainy season runs April–October, when most of the year's rain falls.

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

Is September a good time to visit Sukumo?

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

5.4
Sightseeing
5th-best month of the year
5.9
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Sukumo for sightseeing.

What to pack for Sukumo in September

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

In September, Sukumo sees daytime highs around 28°C and nights near 22°C. Pack light clothes and rain gear. About 15 days see rain.

light clothesrain gear

Sea temperature near Sukumo in September

The nearest coast averages about 27°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 28°C and coldest in February near 18°C.

It's comfortable for a long swim from May 1 to Dec 23 — about 7.8 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan19Cool
Feb18Cool
Mar18Cool
Apr19Cool
May21Refreshing
Jun23Refreshing
Jul26Warm
Aug28Warm
Sep27Warm
Oct25Warm
Nov23Refreshing
Dec20Refreshing

UV index in Sukumo in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sukumo peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJun 23UV 11Dec 23UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug10Very high
Sep10Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Sukumo 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 Sukumo is worst in April — around 20 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodApr 1420 µg/m³Oct 1410 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb15Moderate
Mar19Moderate
Apr20Moderate
May18Moderate
Jun15Moderate
Jul11Good
Aug11Good
Sep10Good
Oct10Good
Nov11Good
Dec10Good
Location & terrain

Where is Sukumo?

Sukumo sits at 32.9°N, 132.7°E, 12 m above sea level, in Japan. The nearest listed city is Mishōhirajō, 16 km away.

Topography around Sukumo

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

Within 3 km, the terrain around Sukumo has significant variations in elevation — a maximum elevation change of 454 m around an average of 116 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,052 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,528 m.

The land around Sukumo is covered by trees (76%) within 3 km, trees (79%) within 16 km, and water (62%) and trees (36%) within 80 km.

3 km
454 m
16 km
1,052 m
80 km
1,528 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Mishōhirajō 16 km · Nakamura 19 km · Shimoda 24 km · Uwajima 36 km · Uwa 52 km · Yawatahama 65 km · Ōzu 65 km · Uchiko 69 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 Sukumo (32.9333°, 132.7333°, elevation 12 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).