Climate and average weather in Amakusa

In Amakusa, the summers are muggy, hot, wet, and partly cloudy and the winters are cool and partly cloudy.

Best: early April to early June

Over the course of the year, the temperature in Amakusa typically varies from 5°C to 32°C, and is rarely below 1°C or above 36°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 Amakusa for warm-weather activities are from early April to early June and late September to late November.

Hottest
Aug
32°
Coldest
Jan
Wettest
Jun
445 mm
Driest
Jan
69 mm
Rain / yr
2096 mm
140 wet days
Daylight
9.9–14.1 h
shortest–longest
Elevation
6 m
32.5°N
Clearest
Oct
47% cloud

Amakusa 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 April to early June.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Amakusa, 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 25 to September 29, with daily high temperatures above 27°C. The hottest month of the year in Amakusa is August, with an average high of 32°C and low of 25°C.

The cool season lasts 3.3 months, from December 3 to March 11, with daily high temperatures below 15°C. The coldest month of the year in Amakusa is January, with an average low of 5°C and high of 11°C.

Days typically run about 7°C warmer than nights year-round.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan115
Feb136
Mar169
Apr2113
May2517
Jun2721
Jul3125
Aug3225
Sep2922
Oct2517
Nov1912
Dec147

How hot and cold Amakusa 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, Amakusa feels like about 39°C (around August 4). About 73 days a year carry some heat stress, and 11 of them tip into dangerous heat (feels-like above 39°C), peaking in August.

10°20°30°40°JanFebMarAprMayJunJulAugSepOctNovDecdangerous heat
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan111135
Feb131336
Mar161679
Apr20211313
May24251717
Jun28272121
Jul36312525
Aug38322525
Sep31292222
Oct25251717
Nov19191212
Dec141457

Average hourly temperature in Amakusa

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 32°C, and coldest before dawn in January, near C.

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

Amakusa weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan11° / 698.410.13.0
Feb13° / 879.110.83.4
Mar16° / 13111.511.84.8
Apr21° / 13°1521112.86.1
May25° / 17°18111.113.66.5
Jun27° / 21°44517.414.15.0
Jul31° / 25°36619.113.93.6
Aug32° / 25°18315.513.23.4
Sep29° / 22°19712.812.25.0
Oct25° / 17°1048.111.27.2
Nov19° / 12°1018.410.36.3
Dec14° / 817.49.94.1

Chance of rain

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

Amakusa gets about 2096 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 3.7 months, from around Jun 2 to Sep 21, peaking in June at about 75% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Dec 21.

June is the wettest month by volume, with 445 mm over about 17 wet days; January is the driest, with 69 mm.

0%10%20%30%40%50%60%70%80%90%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetJun 30 · 75%Dec 21 · 23%
Rain on a day (%)Rain days
Jan278
Feb329
Mar3712
Apr3711
May3611
Jun5817
Jul6119
Aug5016
Sep4213
Oct278
Nov288
Dec247

Monthly rainfall

Over a full year, Amakusa collects about 2096 mm of rain across 140 wet days — roughly 175 mm in an average month.

It doesn’t fall evenly. June is the wettest month with 445 mm, while January is the driest at just 69 mm. The three wettest months alone bring about 48% of the year’s total.

050100150200250300350400450500JanFebMarAprMayJunJulAugSepOctNovDec698713115218144536618319710410181
Rainfall (mm)Rain days
Jan698
Feb879
Mar13112
Apr15211
May18111
Jun44517
Jul36619
Aug18316
Sep19713
Oct1048
Nov1018
Dec817

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

In Amakusa, 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 25 and lasts for 5.3 months, ending around December 31. 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 April 3 and lasts for 3.7 months, ending around July 24. The cloudiest month is June, when it is overcast or mostly cloudy 81% 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 17 · 63%Jun 24 · 13%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearer
Clearer (%)Cloudier (%)
Jan3763
Feb4060
Mar4357
Apr4159
May3763
Jun1981
Jul3169
Aug4654
Sep5050
Oct6139
Nov5545
Dec4654

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 8, brings about 14 h 06 min of light; the shortest, around January 1, only 9 h 54 min — a swing of roughly 4 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan10.17:265:31
Feb10.87:095:58
Mar11.86:366:21
Apr12.85:556:43
May13.65:267:05
Jun14.15:167:23
Jul13.95:277:23
Aug13.25:476:59
Sep12.26:086:19
Oct11.26:295:40
Nov10.36:555:14
Dec9.97:195:12

Sunny days

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

Amakusa averages about 9 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 2 and 15 days.

The sunnier stretch runs 3.6 months, from around Aug 24 to Dec 10. The sunniest month is October, with roughly 14 sunny days (mixed).

The greyest month is June, down near 3 sunny days — about 75% fewer than the October peak.

05101520JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergloomymixedbrightOct 2015 daysJun 242 days
Sunny daysSky
Jan6Gloomy
Feb7Gloomy
Mar9Mixed
Apr9Mixed
May8Gloomy
Jun3Gloomy
Jul6Gloomy
Aug9Mixed
Sep10Mixed
Oct14Mixed
Nov12Mixed
Dec8Mixed

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 Amakusa, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 4.9 months, from around May 15 to October 11. 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 12 to May 14, and March is the most comfortable month — the air is dry or comfortable 99% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecMar 5 · 100%Jul 9 · 0%miserablehumiddryoppressivemuggycomfortablecomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan9910000
Feb9721000
Mar9271000
Apr672010300
May2531291420
Jun272136259
Jul00094248
Aug00274447
Sep4916273212
Oct3926181240
Nov78146200
Dec9730000

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 Amakusa is typically calm, near 10 km/h, and varies little with the seasons.

The windier part of the year lasts 5.1 months, from around Nov 16 to Apr 19. The windiest month is March, averaging about 11 km/h (calm).

The calmer part of the year runs from around Apr 20 to Jun 25, with June the calmest month at about 9 km/h.

051015JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezeMar 9 · 12 km/hJun 3 · 8 km/h
Wind speed (km/h)Feels
Jan11calm
Feb11calm
Mar11calm
Apr10calm
May9calm
Jun9calm
Jul10calm
Aug9calm
Sep9calm
Oct10calm
Nov10calm
Dec11calm

Hazard calendar for Amakusa

In seasonPeak

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

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

Amakusa's rainy season runs June–July, when most of the year's rain falls.

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

Best time to visit Amakusa

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around late May, Amakusa is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.

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 Amakusa for general outdoor tourist activities run from mid April to early June and again from late September to late November, with a peak score in the third week of October.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationOct 20 · 7.5

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
Jan3.0poor
Feb3.4poor
Mar4.8fair
Apr6.1good
May6.5good
Jun5.1fair
Jul3.6fair
Aug3.4poor
Sep5.0fair
Oct7.2good
Nov6.3good
Dec4.2fair

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best times of year to visit Amakusa for hot-weather activities run from early May to mid June and again from late July to late October, with a peak score in the second week of October.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timebeach/pool scoretemperaturecloudsprecipitationOct 11 · 6.7

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 Amakusa, 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 32°C), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 11°C), pack a warm layer and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Amakusa sees daytime highs around 32°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 16 days see rain.

Sea temperature near Amakusa

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 20 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 May 24 to Nov 24 — about 6.1 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Bracing
Mar15Cool
Apr17Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct24Refreshing
Nov21Refreshing
Dec18Cool

UV index (midday) in Amakusa 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 Amakusa peaks around July 13 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 — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 13UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr8Very high
May8Very high
Jun10Very high
Jul11Extreme
Aug9Very high
Sep10Very high
Oct7High
Nov4Moderate
Dec3Moderate

Average hourly UV index in Amakusa

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 8.5 hours a day reach index 3 (protection recommended), and 6 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)
Jan2.50
Feb40
Mar61.5
Apr73.5
May7.54.5
Jun8.55.5
Jul8.56
Aug7.55
Sep7.55
Oct62
Nov40
Dec1.50

Air quality in Amakusa 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 Amakusa is worst in March — around 24 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (July, 13 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2424 µg/m³Jul 2114 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb20Moderate
Mar24Moderate
Apr24Moderate
May22Moderate
Jun18Moderate
Jul13Moderate
Aug14Moderate
Sep14Moderate
Oct14Moderate
Nov16Moderate
Dec15Moderate
Almanac & agriculture

Growing season

Chance of a frost-free dayFrost-free year round

Amakusa 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
Jan970
Feb970
Mar1000
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec990

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. Amakusa banks about 3,137 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
Feb2
Mar72
Apr199
May330
Jun415
Jul546
Aug582
Sep475
Oct338
Nov161
Dec18

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.

Amakusa receives about 4.0 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 2.2 and 5.4 kWh/m².

The brighter stretch of the year lasts 7.0 months, from around Mar 10 to Oct 8. The brightest month is July, averaging about 4.8 kWh/m² (bright).

The dimmest month is December, down near 2.3 kWh/m² — roughly 53% less than the July peak.

0123456JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightJul 315.4 kWhDec 172.2 kWh
Solar energy (kWh/m²)Level
Jan2.4Moderate
Feb3.2Moderate
Mar4.1Bright
Apr5.0Bright
May5.3Bright
Jun4.3Bright
Jul4.9Bright
Aug5.1Bright
Sep4.3Bright
Oct3.8Moderate
Nov2.8Moderate
Dec2.2Moderate

Where is Amakusa?

Amakusa sits at 32.5°N, 130.2°E, 6 m above sea level, in Japan. The nearest listed city is Hondomachi-hondo, 2.0 km away.

Topography around Amakusa

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

Within 3 km, the terrain around Amakusa has significant variations in elevation — a maximum elevation change of 310 m around an average of 40 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 664 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,724 m.

The land around Amakusa is covered by trees (52%), artificial surfaces (22%) and water (20%) within 3 km, trees (54%) and water (40%) within 16 km, and water (48%) and trees (42%) within 80 km.

3 km
310 m
16 km
664 m
80 km
1,724 m
treesgrasslandcroplandartificial surfaceswater
Nearby: Hondomachi-hondo 2.0 km · Minamishimabara 25 km · Ōyanomachi-noboritate 27 km · Ushibukamachi 33 km · Minamata 33 km · Sashiki 34 km · Unzen 35 km · Honmachi 38 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 Amakusa (32.4586°, 130.1931°, elevation 6 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).