Iki weather in September

In September, Iki sees average daytime highs of 25°C and overnight lows near 24°C, with 171 mm of rain across 11.2 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 26°C in the first days to 24°C by the end. The sky is clear or mostly clear about 38% of the time in September, and the air most often feels muggy.

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 Iki's 4th-clearest and 6th-windiest month. For the whole year in context, see Iki's year-round climate.

Daytime high
25°
3rd warmest
Overnight low
24°
10th coldest
Rainfall
171 mm
11.2 wet days
Daylight
12 h 12 min
6:09 AM – 6:22 PM
Cloud cover
56%
4th clearest
Wind
24 km/h
6th windiest
Solar energy
4.29 kWh/m²
Travel score
6.6
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 24°C by the end.

A typical September day in Iki reaches about 25°C in the afternoon and slips back to 24°C overnight — a 1°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.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12725
22725
32625
42625
52625
62625
72625
82625
92625
102624
112624
122624
132524
142524
152524
162524
172524
182523
192523
202523
212423
222423
232423
242423
252423
262422
272422
282422
292322
302322

How September really feels in Iki

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.

Iki 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 daysSnow daysDaylight (hours)Travel score
Jan10° / 7811.90.5102.2
Feb11° / 7810.20.410.72.4
Mar13° / 10°12611.2011.73.4
Apr16° / 14°13410.1012.84.9
May19° / 17°1389.5013.76.1
Jun22° / 21°25112.6014.25.9
Jul26° / 24°24312.90146.2
Aug27° / 26°15811.2013.36.3
Sep25° / 24°17111.2012.26.6
Oct21° / 20°1007.6011.17.1
Nov17° / 15°979.2010.25.7
Dec13° / 10°79110.29.83.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% 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 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15149
25149
35149
45248
55248
65248
75347
85347
95347
105446
115446
125446
135347
145347
155347
165347
175248
185248
195248
205149
215149
225149
235149
245149
255248
265248
275248
285248
295347
305347

Chance of precipitation in September

Any precipitation

Iki gets around 171 mm of rain over 11.2 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 37% and peaks near 43% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
143
243
342
442
542
642
742
841
941
1041
1140
1240
1339
1438
1537
1637
1736
1835
1935
2034
2134
2233
2333
2432
2532
2631
2731
2830
2930
3030

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 30% 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 (%)
1003244231
2004254229
3004274226
4005284224
5016294222
6017304220
7018314219
8019314217
90110324116
100211334014
110313333913
120314333712
130415333611
140517333410
151618333310
16172033319
17182133298
18192232278
192102332267
202112432246
212122532236
223132631215
233152731204
244162830194
254172930173
265182929163
275202928152
286213028142
297223027131
308233026121

Wind in September

Winds average 24 km/h in September.

Across September, daily wind ranges from about 22 km/h on the calmest days to 25 km/h at its breeziest. It stays fairly steady from day to day.

0102030151015202530
Wind speed (km/h)Feels
122breezy
222breezy
322breezy
422breezy
523breezy
623breezy
723breezy
823breezy
923breezy
1023breezy
1123breezy
1223breezy
1324breezy
1424breezy
1524breezy
1624breezy
1724breezy
1824breezy
1925breezy
2025breezy
2125breezy
2225breezy
2325breezy
2425breezy
2525breezy
2625breezy
2725breezy
2825breezy
2925breezy
3025breezy

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 5:59 AM to 6:19 AM, and sunset from 6:43 PM to 6:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:596:43
212.75:596:42
312.76:006:40
412.66:016:39
512.66:026:37
612.66:026:36
712.56:036:35
812.56:046:33
912.56:046:32
1012.46:056:30
1112.46:066:29
1212.36:066:27
1312.36:076:26
1412.36:086:25
1512.26:096:23
1612.26:096:22
1712.26:106:20
1812.16:116:19
1912.16:116:17
2012.16:126:16
2112.06:136:14
2212.06:136:13
2312.06:146:12
2411.96:156:10
2511.96:166:09
2611.86:166:07
2711.86:176:06
2811.86:186:04
2911.76:196:03
3011.76:196:02

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.29 kWh/m².

For context, solar energy here swings from a low near 2.19 kWh/m² to a high of 5.6 kWh/m² in May across the year — September's 4.29 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.6Bright
24.6Bright
34.6Bright
44.6Bright
54.5Bright
64.5Bright
74.5Bright
84.5Bright
94.5Bright
104.4Bright
114.4Bright
124.4Bright
134.4Bright
144.3Bright
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 Iki

In seasonPeak

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

Iki 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 Iki?

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

6.6
Sightseeing
2nd-best month of the year
6.0
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Iki for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Iki in September

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

In September, Iki sees daytime highs around 25°C and nights near 24°C. Worth packing: light clothes, rain gear and a windbreaker. About 11 days see rain.

light clothesrain geara windbreaker

Sea temperature near Iki in September

The nearest coast averages about 26°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 14 km away) is warmest in August at about 27°C and coldest in February near 15°C.

It's comfortable for a long swim from Jun 6 to Nov 26 — about 5.7 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Bracing
Mar15Bracing
Apr16Cool
May18Cool
Jun21Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Iki in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Iki peaks around July 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 23UV 9Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr8Very high
May8Very high
Jun8Very high
Jul9Very high
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Iki 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 Iki is worst in April — around 24 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (July, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateApr 924 µg/m³Jul 2211 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb20Moderate
Mar24Moderate
Apr24Moderate
May21Moderate
Jun16Moderate
Jul11Good
Aug11Good
Sep12Good
Oct11Good
Nov14Moderate
Dec13Moderate
Location & terrain

Where is Iki?

Iki sits at 33.8°N, 129.7°E, 45 m above sea level, in Japan. The nearest listed city is Karatsu, 44 km away.

Topography around Iki

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

Within 3 km, the terrain around Iki has only modest variations in elevation — a maximum elevation change of 152 m around an average of 64 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 208 m; within 80 km, large variations in elevation — a maximum elevation change of 1,043 m.

The land around Iki is covered by trees (72%) within 3 km, water (83%) within 16 km, and water (77%) within 80 km.

3 km
152 m
16 km
208 m
80 km
1,043 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Karatsu 44 km · Hirado 49 km · Matsuura 49 km · Itoshima 51 km · Maebaru-chūō 51 km · Imarichō-kō 58 km · Tsushima 62 km · Shingū 66 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 Iki (33.7829°, 129.7209°, elevation 45 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).