Karatsu weather in August

In August, Karatsu sees average daytime highs of 29°C and overnight lows near 26°C, with 162 mm of rain across 13.7 wet days and about 13.2 hours of daylight. It is the 1st-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 33% of the time in August, and the air most often feels miserable.

Daylight stretches from about 13 h 42 min at the start of August to 12 h 48 min by month's end. Set against the rest of the year, August is Karatsu's 5th-clearest and 10th-windiest month. For the whole year in context, see Karatsu's year-round climate.

Daytime high
29°
1st warmest
Overnight low
26°
12th coldest
Rainfall
162 mm
13.7 wet days
Daylight
13 h 18 min
5:47 AM – 7:02 PM
Cloud cover
61%
5th clearest
Wind
12 km/h
10th windiest
Solar energy
4.94 kWh/m²
Travel score
4.9
out of 10

Karatsu is city in Saga Prefecture, Japan.

Density
241/km²
people per km²
Founded
2005

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical August day in Karatsu reaches about 29°C in the afternoon and slips back to 26°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 31°C. Set against its neighbours, August runs about 2°C warmer than July and about 3°C warmer than September.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13026
23026
33026
43026
53026
63026
73026
83026
93026
103026
113026
123026
133026
143026
153026
163026
172926
182926
192926
202926
212925
222925
232925
242925
252925
262925
272925
282925
292925
302825
312825

How August really feels in Karatsu

Once humidity and wind are folded in, August averages 28 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
28
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in August is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Karatsu weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7711.81.2101.9
Feb10° / 7810.30.810.82.2
Mar13° / 12411.60.211.73.5
Apr17° / 12°13411012.85.3
May21° / 16°14310.3013.76.4
Jun24° / 20°27714.7014.25.8
Jul28° / 24°26015.40145.1
Aug29° / 26°16213.7013.24.9
Sep26° / 22°17912.6012.26.2
Oct22° / 18°1038.1011.27.1
Nov17° / 13°959.3010.35.5
Dec12° / 8111.10.39.83.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 14% of August, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15149
25149
35050
44951
54951
64852
74654
84654
94555
104555
114456
124456
134357
144357
154357
164357
174357
184456
194555
204654
214654
224753
234654
244753
254753
264753
274753
284852
294951
304951
314951

Chance of precipitation in August

Any precipitation

Karatsu gets around 162 mm of rain over 13.7 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 45% and peaks near 47% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
140
240
341
441
541
642
742
842
943
1043
1144
1244
1345
1445
1545
1646
1746
1846
1946
2046
2146
2246
2346
2447
2547
2647
2747
2847
2947
3047
3147

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

Most of August feels miserable — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, August lands in the miserable band about 51% of days. Sticky, muggy-or-worse air turns up on roughly 99% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1033562
2033562
3033562
4033463
5023563
6023563
7023563
8023563
9023662
10023662
11023761
12023761
13033859
14033958
15134056
16144055
17144154
18154252
19164251
20174349
21184447
22194545
232104643
242114640
252124738
262144836
273154934
283174931
293185029
303195127
314215025

Wind in August

Winds average 12 km/h in August.

Across August, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1112calm
1212calm
1312calm
1412calm
1512calm
1612calm
1712calm
1812calm
1912calm
2012calm
2112calm
2212calm
2312calm
2412light breeze
2512light breeze
2612light breeze
2712light breeze
2812light breeze
2912light breeze
3013light breeze
3113light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 42 min at the start of August to 12 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 54 minutes over August. Sunrise moves from 5:36 AM to 5:57 AM, and sunset from 7:16 PM to 6:43 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:367:16
213.65:377:16
313.65:377:15
413.65:387:14
513.65:397:13
613.55:407:12
713.55:407:11
813.55:417:10
913.55:427:09
1013.45:427:08
1113.45:437:07
1213.45:447:06
1313.35:457:05
1413.35:457:04
1513.35:467:03
1613.35:477:02
1713.25:477:01
1813.25:486:59
1913.25:496:58
2013.15:506:57
2113.15:506:56
2213.15:516:55
2313.05:526:53
2413.05:526:52
2513.05:536:51
2612.95:546:50
2712.95:556:48
2812.95:556:47
2912.85:566:46
3012.85:576:44
3112.85:576:43

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 4.94 kWh/m².

For context, solar energy here swings from a low near 2.14 kWh/m² to a high of 5.41 kWh/m² in May across the year — August's 4.94 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.3Bright
65.2Bright
75.2Bright
85.2Bright
95.2Bright
105.1Bright
115.1Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
164.9Bright
174.9Bright
184.9Bright
194.8Bright
204.8Bright
214.8Bright
224.8Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.6Bright
284.6Bright
294.6Bright
304.5Bright
314.5Bright
Planning a trip in August

Hazard calendar for Karatsu

In seasonPeak

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

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

Karatsu's rainy season runs April–September, 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 August a good time to visit Karatsu?

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

4.9
Sightseeing
8th-best month of the year
6.3
Beach & pool
1st-best month of the year

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

What to pack for Karatsu in August

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

In August, Karatsu sees daytime highs around 29°C and nights near 26°C. Pack light clothes. Worth having: rain gear and sun protection. About 14 days see rain.

light clothesrain gearsun protection

Sea temperature near Karatsu in August

The nearest coast averages about 27°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 22 km away) is warmest in August at about 27°C and coldest in February near 14°C.

It's comfortable for a long swim from Jun 8 to Nov 21 — about 5.5 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb14Bracing
Mar14Bracing
Apr16Cool
May18Cool
Jun21Refreshing
Jul24Warm
Aug27Warm
Sep25Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Karatsu in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Karatsu 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
Jun7Very high
Jul9Very high
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Karatsu in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Karatsu 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 Karatsu?

Karatsu sits at 33.4°N, 130.0°E, 7 m above sea level, in Japan. The nearest listed city is Imarichō-kō, 21 km away.

Topography around Karatsu

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

Within 3 km, the terrain around Karatsu has only modest variations in elevation — a maximum elevation change of 218 m around an average of 38 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 899 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,318 m.

The land around Karatsu is covered by trees (41%), artificial surfaces (28%) and water (24%) within 3 km, trees (59%) and water (29%) within 16 km, and water (58%) and trees (29%) within 80 km.

3 km
218 m
16 km
899 m
80 km
1,318 m
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Imarichō-kō 21 km · Taku 23 km · Itoshima 23 km · Maebaru-chūō 25 km · Ogi 28 km · Matsuura 28 km · Takeo 28 km · Arita 30 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 Karatsu (33.4425°, 129.9697°, elevation 7 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).