Climate and average weather in Iki

In Iki, the summers are oppressive, warm, showery, and partly cloudy and the winters are cool, windy, and mostly cloudy.

Best: early July to mid November

Over the course of the year, the temperature in Iki typically varies from 8°C to 27°C, and is rarely below 3°C or above 29°C. August is the hottest month of the year, while January is the coldest.

Based on the travel score, the best times of year to visit Iki for warm-weather activities are from early May to late June and early July to mid November.

Hottest
Aug
27°
Coldest
Jan
Wettest
Jun
251 mm
Driest
Feb
78 mm
Rain / yr
1653 mm
129 wet days
Daylight
9.8–14.2 h
shortest–longest
Elevation
45 m
33.8°N
Clearest
Oct
48% cloud

Iki weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early July to mid November.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Iki, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 3.2 months, from June 27 to October 1, with daily high temperatures above 23°C. The hottest month of the year in Iki is August, with an average high of 27°C and low of 26°C.

The cool season lasts 3.4 months, from December 10 to March 22, with daily high temperatures below 13°C. The coldest month of the year in Iki is January, with an average low of 8°C and high of 10°C.

Days typically run about 2°C warmer than nights year-round.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan108
Feb118
Mar1310
Apr1614
May1917
Jun2221
Jul2624
Aug2726
Sep2524
Oct2120
Nov1715
Dec1310

How hot and cold Iki really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the hottest afternoons, once humidity is folded in, Iki feels like about 32°C (around August 6). About 5 days a year carry some heat stress, peaking in August.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan101048
Feb111148
Mar1313910
Apr16161414
May19191717
Jun22222121
Jul26262424
Aug31272626
Sep25252424
Oct21212020
Nov17171515
Dec1313810

Average hourly temperature in Iki

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 27°C, and coldest before dawn in January, near C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Iki weather by month

Every month at a glance. Click a month for its detailed page.

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

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Iki gets about 1653 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.

The wetter season lasts 1.3 months, from around Jun 11 to Jul 20, peaking in June at about 56% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Oct 14.

June is the wettest month by volume, with 251 mm over about 13 wet days; February is the driest, with 78 mm.

0%10%20%30%40%50%60%70%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetJun 30 · 56%Oct 14 · 24%
Rain on a day (%)Rain days
Jan3812
Feb3710
Mar3611
Apr3410
May3110
Jun4213
Jul4213
Aug3611
Sep3711
Oct258
Nov309
Dec3511

Monthly rainfall

Over a full year, Iki collects about 1653 mm of rain across 129 wet days — roughly 138 mm in an average month.

It doesn’t fall evenly. June is the wettest month with 251 mm, while February is the driest at just 78 mm. The three wettest months alone bring about 40% of the year’s total, and some of the cold-season precipitation falls as snow.

050100150200250300JanFebMarAprMayJunJulAugSepOctNovDec78781261341382512431581711009779
Rainfall (mm)Rain daysSnow days
Jan78121
Feb78100
Mar126110
Apr134100
May138100
Jun251130
Jul243130
Aug158110
Sep171110
Oct10080
Nov9790
Dec79110

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Iki, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around July 21 and lasts for 4.4 months, ending around December 2. The clearest month is October, when the sky is clear, mostly clear, or partly cloudy 61% of the time on average.

The cloudier part of the year begins around May 26 and lasts for 1.8 months, ending around July 20. The cloudiest month is June, when it is overcast or mostly cloudy 69% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecOct 16 · 63%Jun 29 · 22%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan3169
Feb3763
Mar4555
Apr4852
May4555
Jun3169
Jul3862
Aug5050
Sep5248
Oct6139
Nov5248
Dec4060

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 7, brings about 14 h 12 min of light; the shortest, around January 1, only 9 h 48 min — a swing of roughly 4 h 24 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan10.07:315:30
Feb10.77:135:58
Mar11.76:396:23
Apr12.85:566:47
May13.75:257:10
Jun14.25:147:28
Jul14.05:257:28
Aug13.35:477:03
Sep12.26:096:22
Oct11.16:325:40
Nov10.27:005:13
Dec9.87:245:10

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Iki averages about 9 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 4 and 15 days.

The sunnier stretch runs 4.2 months, from around Jul 20 to Nov 25. The sunniest month is October, with roughly 14 sunny days (mixed).

The greyest month is January, down near 5 sunny days — about 67% fewer than the October peak.

05101520JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedbrightOct 1615 daysJan 194 days
Sunny daysSky
Jan5Gloomy
Feb6Gloomy
Mar10Mixed
Apr11Mixed
May10Mixed
Jun6Gloomy
Jul8Mixed
Aug12Mixed
Sep12Mixed
Oct14Mixed
Nov10Mixed
Dec7Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In Iki, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 5.0 months, from around May 16 to October 13. The muggiest month is July, when the air feels humid, muggy or worse about 100% of the time.

The most comfortable stretch runs from around October 14 to May 15, and January is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 7 · 100%Jul 9 · 0%miserableoppressivemuggyhumidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan10000000
Feb9910000
Mar9640000
Apr71254000
May213636700
Jun153044191
Jul002144539
Aug00183161
Sep2918303012
Oct3528231130
Nov80136100
Dec9820000

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Iki is typically breezy, near 23 km/h, and varies moderately with the seasons.

The windier part of the year lasts 7.0 months, from around Sep 10 to Apr 9. The windiest month is January, averaging about 27 km/h (breezy).

The calmer part of the year runs from around Apr 10 to Sep 9, with June the calmest month at about 19 km/h.

051015202530JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezywindyJan 19 · 27 km/hJun 2 · 18 km/h
Wind speed (km/h)Feels
Jan27breezy
Feb26breezy
Mar25breezy
Apr22breezy
May20light breeze
Jun19light breeze
Jul20breezy
Aug20breezy
Sep24breezy
Oct24breezy
Nov24breezy
Dec26breezy

Hazard calendar for Iki

In seasonPeak

When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.

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

Best time to visit Iki

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Iki throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around mid July, Iki is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best times of year to visit Iki for general outdoor tourist activities run from early May to late June and again from early July to mid November, with a peak score in the second week of October.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationOct 9 · 7.2

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan2.2poor
Feb2.4poor
Mar3.4poor
Apr4.9fair
May6.1good
Jun5.9good
Jul6.2good
Aug6.3good
Sep6.7good
Oct7.0good
Nov5.6good
Dec3.4poor

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Iki for hot-weather activities is from mid July to early October, with a peak score in the first week of August.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationAug 3 · 6.9

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Iki, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around August (highs near 27°C), the essentials are light clothes, rain gear, sun protection and a windbreaker. In the cold season around January (highs near 10°C), pack a warm layer, rain gear and a windbreaker.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Iki sees daytime highs around 27°C and nights near 26°C. Pack light clothes. Worth having: rain gear, sun protection and a windbreaker. About 11 days see rain.

Sea temperature near Iki

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

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 (midday) in Iki by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

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

Average hourly UV index in Iki

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in July the burn window is concentrated in the middle of the day: about 8 hours a day reach index 3 (protection recommended), and 5.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan00
Feb3.50
Mar5.50
Apr73.5
May7.54.5
Jun7.54
Jul85.5
Aug7.55
Sep7.55
Oct5.51.5
Nov30
Dec00

Air quality in Iki by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly 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
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Iki is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecfrost-free year round
Frost-free chance (%)Frost nights
Jan1000
Feb1000
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec1000

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Iki banks about 2,725 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

01,0002,0003,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan0
Feb0
Mar45
Apr139
May249
Jun336
Jul464
Aug519
Sep431
Oct325
Nov179
Dec39

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Iki receives about 4.1 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.2 and 5.7 kWh/m².

The brighter stretch of the year lasts 6.6 months, from around Mar 10 to Sep 26. The brightest month is May, averaging about 5.6 kWh/m² (bright).

The dimmest month is December, down near 2.2 kWh/m² — roughly 60% less than the May peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseMay 245.7 kWhDec 162.2 kWh
Solar energy (kWh/m²)Level
Jan2.3Moderate
Feb3.2Moderate
Mar4.3Bright
Apr5.2Bright
May5.6Bright
Jun5.0Bright
Jul5.1Bright
Aug5.1Bright
Sep4.3Bright
Oct3.7Moderate
Nov2.7Moderate
Dec2.2Moderate

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
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).