Climate and average weather in Sōsa

In Sōsa, the summers are muggy, hot, showery, and partly cloudy and the winters are cool and mostly clear.

Best: mid April to early August

Over the course of the year, the temperature in Sōsa typically varies from 3°C to 29°C, and is rarely below 0°C or above 33°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 Sōsa for warm-weather activities are from mid April to early August and late August to mid November.

Hottest
Aug
29°
Coldest
Jan
Wettest
Oct
209 mm
Driest
Feb
77 mm
Rain / yr
1493 mm
140 wet days
Daylight
9.6–14.4 h
shortest–longest
Elevation
36 m
35.7°N
Clearest
Jan
41% cloud

Sōsa 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 mid April to early August.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Sōsa, 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 20 to September 24, with daily high temperatures above 25°C. The hottest month of the year in Sōsa is August, with an average high of 29°C and low of 24°C.

The cool season lasts 3.4 months, from December 6 to March 18, with daily high temperatures below 13°C. The coldest month of the year in Sōsa is January, with an average low of 3°C and high of 9°C.

Days typically run about 6°C warmer than nights year-round.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan93
Feb104
Mar137
Apr1711
May2116
Jun2419
Jul2823
Aug2924
Sep2622
Oct2117
Nov1711
Dec126

How hot and cold Sōsa 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, Sōsa feels like about 34°C (around August 10). About 34 days a year carry some heat stress, peaking in August.

On the coldest nights, wind chill pulls the feels-like down to about -1°C (around January 25), with roughly 33 freezing days a year (feels-like at or below 0°C), worst in January.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan9903
Feb101004
Mar131347
Apr17171011
May21211616
Jun24241919
Jul30282323
Aug33292424
Sep27262222
Oct21211717
Nov17171111
Dec121236

Average hourly temperature in Sōsa

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 29°C, and coldest before dawn in January, near C.

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

Sōsa 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
Jan / 828.70.79.92.1
Feb10° / 7790.810.62.3
Mar13° / 13013.10.511.73.4
Apr17° / 11°11212.6012.95.2
May21° / 16°12811.7013.96.1
Jun24° / 19°15913.2014.45.9
Jul28° / 23°14213.3014.25.4
Aug29° / 24°10111.1013.45.1
Sep26° / 22°16814012.25.8
Oct21° / 17°20913.2011.16.1
Nov17° / 11°10910.9010.15.2
Dec12° / 779.409.63.3

Chance of rain

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

Sōsa gets about 1493 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 1.7 months, from around May 29 to Jul 20, peaking in June at about 50% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Dec 29.

October is the wettest month by volume, with 209 mm over about 13 wet days; February is the driest, with 77 mm.

0%10%20%30%40%50%60%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetJun 30 · 50%Dec 29 · 24%
Rain on a day (%)Rain days
Jan289
Feb339
Mar4113
Apr4213
May3812
Jun4513
Jul4113
Aug3711
Sep4714
Oct4213
Nov3711
Dec309

Monthly rainfall

Over a full year, Sōsa collects about 1493 mm of rain across 140 wet days — roughly 124 mm in an average month.

It doesn’t fall evenly. October is the wettest month with 209 mm, while February is the driest at just 77 mm. The three wettest months alone bring about 36% of the year’s total, and some of the cold-season precipitation falls as snow.

050100150200250JanFebMarAprMayJunJulAugSepOctNovDec827713011212815914210116820910977
Rainfall (mm)Rain daysSnow days
Jan8291
Feb7791
Mar130131
Apr112130
May128120
Jun159130
Jul142130
Aug101110
Sep168140
Oct209130
Nov109110
Dec7790

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

In Sōsa, 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 October 19 and lasts for 5.1 months, ending around March 22. The clearest month is January, when the sky is clear, mostly clear, or partly cloudy 69% of the time on average.

The cloudier part of the year begins around March 23 and lasts for 6.9 months, ending around October 18. The cloudiest month is June, when it is overcast or mostly cloudy 78% 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%JanFebMarAprMayJunJulAugSepOctNovDecJan 3 · 73%Jun 21 · 19%clearmostly clearpartly cloudymostly cloudyovercastclearercloudierclearer
Clearer (%)Cloudier (%)
Jan6931
Feb5743
Mar4753
Apr4456
May3565
Jun2278
Jul2872
Aug4258
Sep3961
Oct4555
Nov5545
Dec6634

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 10, brings about 14 h 24 min of light; the shortest, around January 1, only 9 h 36 min — a swing of roughly 4 h 48 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan9.96:524:42
Feb10.66:335:12
Mar11.75:565:39
Apr12.95:116:05
May13.94:386:30
Jun14.44:266:50
Jul14.24:376:49
Aug13.45:016:23
Sep12.25:255:39
Oct11.15:504:55
Nov10.16:214:25
Dec9.66:464:22

Sunny days

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

Sōsa averages about 10 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 3 and 19 days.

The sunnier stretch runs 5.0 months, from around Oct 20 to Mar 19. The sunniest month is January, with roughly 17 sunny days (bright).

The greyest month is June, down near 4 sunny days — about 77% fewer than the January peak.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecsunniergreyersunniergloomymixedbrightbrilliantJan 119 daysJun 213 days
Sunny daysSky
Jan17Bright
Feb12Mixed
Mar10Mixed
Apr9Mixed
May7Gloomy
Jun4Gloomy
Jul5Gloomy
Aug8Mixed
Sep7Gloomy
Oct10Mixed
Nov12Mixed
Dec17Bright

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

The more humid part of the year lasts 4.7 months, from around May 24 to October 14. The muggiest month is July, when the air feels humid, muggy or worse about 99% of the time.

The most comfortable stretch runs from around October 15 to May 23, and February 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%JanFebMarAprMayJunJulAugSepOctNovDecFeb 24 · 100%Jul 23 · 0%miserableoppressivemuggyhumidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
Jan10000000
Feb10000000
Mar9910000
Apr84132000
May373622400
Jun4163434120
Jul019245511
Aug014155229
Sep491829337
Oct3628221220
Nov82134000
Dec9910000

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.

Wind in Sōsa is steady company: average speeds sit near 14 km/hlight breeze — in every month of the year, with no meaningful windy or calm season.

05101520JanFebMarAprMayJunJulAugSepOctNovDeccalmlight breezeApr 11 · 15 km/hJul 31 · 12 km/h
Wind speed (km/h)Feels
Jan14light breeze
Feb14light breeze
Mar15light breeze
Apr15light breeze
May14light breeze
Jun13light breeze
Jul13light breeze
Aug13light breeze
Sep14light breeze
Oct14light breeze
Nov13light breeze
Dec13light breeze

Hazard calendar for Sōsa

In seasonPeak

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

Sōsa 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 Sōsa

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around late July, Sōsa 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 Sōsa for general outdoor tourist activities run from mid April to early August and again from late August to mid November, with a peak score in the last week of May.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timebest timetravel scoretemperaturecloudsprecipitationMay 29 · 6.3

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
Feb2.3poor
Mar3.4poor
Apr5.2fair
May6.2good
Jun5.9good
Jul5.4fair
Aug5.1fair
Sep5.8good
Oct6.0good
Nov5.2fair
Dec3.3poor

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 Sōsa for hot-weather activities is from early July to late September, with a peak score in the first week of August.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationAug 3 · 6.8

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 Sōsa, 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 29°C), the essentials are light clothes, rain gear and sun protection. In the cold season around January (highs near 9°C), pack a warm layer and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Sōsa sees daytime highs around 29°C and nights near 24°C. Pack light clothes. Worth having: rain gear and sun protection. About 11 days see rain.

Sea temperature near Sōsa

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

The sea offshore is warmest in August at about 25°C and coldest in February near 15°C.

It's comfortable for a long swim from Jun 5 to Nov 22 — about 5.6 months when the water holds above 20°C.

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Bracing
Mar15Cool
Apr16Cool
May19Cool
Jun21Refreshing
Jul23Refreshing
Aug25Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index (midday) in Sōsa 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 Sōsa peaks around August 12 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highModerateAug 12UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar4Moderate
Apr7High
May8Very high
Jun9Very high
Jul10Very high
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec2Moderate

Average hourly UV index in Sōsa

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 August 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
Feb30
Mar4.50
Apr6.52
May7.54.5
Jun85
Jul8.55.5
Aug85.5
Sep74.5
Oct50
Nov2.50
Dec00

Air quality in Sōsa 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 Sōsa is worst in March — around 25 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (December, 14 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2425 µg/m³Dec 1914 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb18Moderate
Mar25Moderate
Apr25Moderate
May24Moderate
Jun19Moderate
Jul16Moderate
Aug15Moderate
Sep15Moderate
Oct16Moderate
Nov16Moderate
Dec14Moderate
Almanac & agriculture

Growing season

Chance of a frost-free day

Sōsa is mild enough that a frost-free day stays more likely than not even in midwinter.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDec
Frost-free chance (%)Frost nights
Jan930
Feb930
Mar990
Apr1000
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct1000
Nov1000
Dec980

Growing degree days

Degree days (base 10°C)

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. Sōsa banks about 2,566 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

01,0002,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan0
Feb0
Mar10
Apr126
May264
Jun354
Jul477
Aug521
Sep417
Oct276
Nov116
Dec5

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.

Sōsa receives about 4.0 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.2 and 5.6 kWh/m².

The brighter stretch of the year lasts 6.2 months, from around Mar 13 to Sep 17. The brightest month is August, averaging about 5.3 kWh/m² (bright).

The dimmest month is December, down near 2.4 kWh/m² — roughly 55% less than the August peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseAug 35.6 kWhDec 42.2 kWh
Solar energy (kWh/m²)Level
Jan2.8Moderate
Feb3.4Moderate
Mar4.1Bright
Apr5.0Bright
May5.4Bright
Jun5.0Bright
Jul5.2Bright
Aug5.3Bright
Sep4.1Bright
Oct3.1Moderate
Nov2.5Moderate
Dec2.3Moderate

Where is Sōsa?

Sōsa sits at 35.7°N, 140.6°E, 36 m above sea level, in Japan. The nearest listed city is Yōkaichiba, 2.0 km away.

Topography around Sōsa

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

Within 3 km, the terrain around Sōsa has only modest variations in elevation — a maximum elevation change of 54 m around an average of 18 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 72 m; within 80 km, large variations in elevation — a maximum elevation change of 840 m.

The land around Sōsa is covered by trees (41%) and cropland (39%) within 3 km, cropland (33%) and trees (32%) within 16 km, and water (42%) and trees (24%) within 80 km.

3 km
54 m
16 km
72 m
80 km
840 m
treesgrasslandcroplandartificial surfaceswater
Nearby: Yōkaichiba 2.0 km · Asahi 9.0 km · Yokoshiba 10 km · Sanmu 16 km · Omigawa 16 km · Ryōgoku 17 km · Narutō 18 km · Sawara 19 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 Sōsa (35.7154°, 140.5531°, elevation 36 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).