Karatsu weather in May

In May, Karatsu sees average daytime highs of 21°C and overnight lows near 16°C, with 143 mm of rain across 10.3 wet days and about 13.7 hours of daylight. It is the 6th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 20°C in the first days to 22°C by the end. The sky is clear or mostly clear about 30% of the time in May, and the air most often feels comfortable.

Daylight stretches from about 13 h 18 min at the start of May to 14 hours by month's end. Set against the rest of the year, May is Karatsu's 7th-clearest and 10th-windiest month. For the whole year in context, see Karatsu's year-round climate.

Daytime high
21°
6th warmest
Overnight low
16°
7th coldest
Rainfall
143 mm
10.3 wet days
Daylight
13 h 42 min
5:25 AM – 7:08 PM
Cloud cover
63%
7th clearest
Wind
12 km/h
10th windiest
Solar energy
5.41 kWh/m²
Travel score
6.4
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 May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 20°C in the first days to 22°C by the end.

A typical May day in Karatsu reaches about 21°C in the afternoon and slips back to 16°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 19°C and 23°C. Set against its neighbours, May runs about 4°C warmer than April and about 3°C cooler than June.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
11914
22015
32015
42015
52015
62015
72015
82015
92016
102116
112116
122116
132116
142116
152116
162116
172117
182117
192217
202217
212217
222217
232217
242217
252218
262218
272218
282218
292218
302318
312318

How May really feels in Karatsu

Once humidity and wind are folded in, May 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

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Karatsu weather by month

How May compares with the rest of the year at a glance. May is the 6th-warmest and 5th-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 May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 12% of May, with mostly cloudy or overcast conditions the remaining 58%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14654
24555
34555
44555
54456
64456
74456
84357
94357
104258
114258
124258
134258
144258
154258
164258
174258
184258
194258
204159
214159
224060
234159
244060
254159
264159
274159
284060
294159
304060
313961

Chance of precipitation in May

Any precipitation

Karatsu gets around 143 mm of rain over 10.3 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 33% and peaks near 34% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
134
234
334
434
534
634
734
834
934
1034
1134
1234
1334
1434
1534
1634
1734
1834
1933
2033
2133
2233
2333
2433
2533
2632
2732
2832
2932
3032
3132

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the comfortable band about 37% of days. Sticky, muggy-or-worse air turns up on roughly 7% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
151341320
249351320
348361430
446361530
544371630
642371730
741381740
839381840
938391940
1036391950
1135402050
1233402150
1332412250
1430412360
1529412460
1627412660
1725422860
1823412960
1921413160
2020413370
2118403570
2217393670
2316383880
2414374080
2513364290
26123444100
27113246110
28103047120
2992949140
3082750160
3172550181

Wind in May

Winds average 12 km/h in May.

Across May, 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
113light breeze
212light breeze
312light breeze
412light breeze
512light breeze
612light breeze
712light breeze
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light breeze
1312calm
1412calm
1512calm
1612calm
1712calm
1812calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2911calm
3011calm
3111calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 18 min at the start of May to 14 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over May. Sunrise moves from 5:38 AM to 5:17 AM, and sunset from 6:57 PM to 7:18 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.35:386:57
213.35:376:57
313.45:366:58
413.45:356:59
513.45:347:00
613.55:337:01
713.55:327:01
813.55:317:02
913.55:307:03
1013.65:297:04
1113.65:297:04
1213.65:287:05
1313.65:277:06
1413.75:267:07
1513.75:257:07
1613.75:257:08
1713.75:247:09
1813.85:237:10
1913.85:237:10
2013.85:227:11
2113.85:217:12
2213.95:217:12
2313.95:207:13
2413.95:207:14
2513.95:197:15
2613.95:197:15
2714.05:187:16
2814.05:187:17
2914.05:177:17
3014.05:177:18
3114.05:177:18

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.41 kWh/m² — the sunniest month for solar.

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 — May's 5.41 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
65.3Bright
75.3Bright
85.3Bright
95.3Bright
105.3Bright
115.3Bright
125.3Bright
135.4Bright
145.4Bright
155.4Bright
165.4Bright
175.4Bright
185.4Bright
195.5Bright
205.5Bright
215.5Bright
225.5Bright
235.5Bright
245.5Bright
255.5Bright
265.5Bright
275.5Bright
285.5Bright
295.4Bright
305.4Bright
315.4Bright
Planning a trip in May

Hazard calendar for Karatsu

In seasonPeak

In May, 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 May a good time to visit Karatsu?

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

6.4
Sightseeing
2nd-best month of the year
4.0
Beach & pool
6th-best month of the year

May is a reasonable time to visit Karatsu for sightseeing.

What to pack for Karatsu in May

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

In May, Karatsu sees daytime highs around 21°C and nights near 16°C. Worth packing: rain gear and sun protection. About 10 days see rain.

rain gearsun protection

Sea temperature near Karatsu in May

The nearest coast averages about 18°C in May — 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 May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 8 (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 May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May 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
May 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).