Usuki weather in September

In September, Usuki sees average daytime highs of 28°C and overnight lows near 21°C, with 229 mm of rain across 14.6 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 30°C in the first days to 26°C by the end. The sky is clear or mostly clear about 29% 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 Usuki's 8th-clearest and 9th-windiest month. For the whole year in context, see Usuki's year-round climate.

Daytime high
28°
3rd warmest
Overnight low
21°
10th coldest
Rainfall
229 mm
14.6 wet days
Daylight
12 h 12 min
6:01 AM – 6:13 PM
Cloud cover
62%
8th clearest
Wind
8 km/h
9th windiest
Solar energy
4.3 kWh/m²
Travel score
5.4
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 30°C in the first days to 26°C by the end.

A typical September day in Usuki reaches about 28°C in the afternoon and slips back to 21°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 31°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13023
23023
33023
43023
53023
62923
72923
82922
92922
102922
112922
122822
132822
142821
152821
162821
172821
182721
192721
202720
212720
222720
232720
242620
252619
262619
272619
282619
292619
302619

How September really feels in Usuki

Once humidity and wind are folded in, September averages 6 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
6
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.

Usuki 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
Jan11° / 565.40.410.12.9
Feb12° / 6470.610.83.3
Mar15° / 9710.2011.74.7
Apr20° / 11°11710.2012.86.2
May24° / 15°14110.9013.76.6
Jun27° / 20°29116.4014.15.2
Jul31° / 24°21716.40143.8
Aug31° / 24°20717.4013.23.6
Sep28° / 21°22914.6012.25.4
Oct23° / 15°1508.4011.27.2
Nov18° / 10°796.9010.36.2
Dec13° / 565.709.94.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% 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 54%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14456
24456
34456
44555
54456
64456
74456
84357
94357
104456
114456
124555
134456
144456
154456
164555
174555
184555
194654
204654
214753
224753
234852
244852
254951
264951
275050
284852
294951
304951

Chance of precipitation in September

Any precipitation

Usuki gets around 229 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 48% and peaks near 55% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
155
254
354
453
553
652
752
852
951
1051
1150
1250
1349
1449
1548
1648
1747
1847
1947
2046
2146
2245
2344
2444
2543
2642
2742
2841
2940
3039

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 37% of days. Sticky, muggy-or-worse air turns up on roughly 69% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1015205915
2016215913
3016225912
4017225911
5018235810
602924569
7021025558
8021126547
9121226527
10131327506
11131427486
12141628456
13251728436
14251828415
15261928395
16272029375
17382228345
18392328324
193102428304
204112528284
214122628264
224132728243
235142828223
245152927213
255172927192
266183027182
277193026162
287203126151
298213125141
309223125131

Wind in September

Winds average 8 km/h in September.

Across September, daily wind ranges from about 8 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

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 5:51 AM to 6:11 AM, and sunset from 6:34 PM to 5:53 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:516:34
212.75:526:33
312.75:526:31
412.65:536:30
512.65:546:29
612.55:546:27
712.55:556:26
812.55:566:24
912.45:566:23
1012.45:576:22
1112.45:586:20
1212.35:586:19
1312.35:596:17
1412.36:006:16
1512.26:006:15
1612.26:016:13
1712.26:026:12
1812.16:026:10
1912.16:036:09
2012.16:046:07
2112.06:046:06
2212.06:056:05
2312.06:066:03
2411.96:076:02
2511.96:076:00
2611.96:085:59
2711.86:095:58
2811.86:095:56
2911.76:105:55
3011.76:115:53

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.3 kWh/m².

For context, solar energy here swings from a low near 2.49 kWh/m² to a high of 5.5 kWh/m² in May across the year — September's 4.3 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
114.5Bright
124.4Bright
134.4Bright
144.4Bright
154.3Bright
164.3Bright
174.3Bright
184.3Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.1Bright
244.1Bright
254.1Bright
264.1Bright
274.0Bright
284.0Bright
294.0Bright
304.0Moderate
Planning a trip in September

Hazard calendar for Usuki

In seasonPeak

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

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

Usuki's rainy season runs May–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 Usuki?

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
6.0
Beach & pool
1st-best month of the year

September is a reasonable time to visit Usuki for sightseeing.

What to pack for Usuki in September

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

In September, Usuki sees daytime highs around 28°C and nights near 21°C. Pack light clothes and rain gear. About 15 days see rain.

light clothesrain gear

Sea temperature near Usuki 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 at the nearest coast (about 29 km away) is warmest in August at about 26°C and coldest in February near 14°C.

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

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb14Bracing
Mar14Bracing
Apr16Cool
May18Cool
Jun21Refreshing
Jul24Warm
Aug26Warm
Sep25Warm
Oct23Refreshing
Nov20Refreshing
Dec18Cool

UV index in Usuki 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 Usuki peaks around June 21 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highModerateJun 21UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May8Very high
Jun10Extreme
Jul10Very high
Aug9Very high
Sep10Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Usuki 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 Usuki is worst in April — around 23 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (October, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodGoodApr 1523 µg/m³Oct 1611 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb17Moderate
Mar22Moderate
Apr23Moderate
May22Moderate
Jun19Moderate
Jul16Moderate
Aug16Moderate
Sep12Moderate
Oct11Good
Nov12Moderate
Dec12Good
Location & terrain

Where is Usuki?

Usuki sits at 33.1°N, 131.8°E, 4 m above sea level, in Japan. The nearest listed city is Tsukumiura, 8.0 km away.

Topography around Usuki

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

Within 3 km, the terrain around Usuki has significant variations in elevation — a maximum elevation change of 460 m around an average of 65 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 716 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,758 m.

The land around Usuki is covered by trees (56%) and water (21%) within 3 km, trees (61%) and water (27%) within 16 km, and water (49%) and trees (45%) within 80 km.

3 km
460 m
16 km
716 m
80 km
1,758 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Tsukumiura 8.0 km · Tsurusaki 17 km · Saiki 21 km · Ōita 23 km · Mie 27 km · Beppu 33 km · Kitsuki 37 km · Hiji 37 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 Usuki (33.1234°, 131.804°, 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).