Karatsu weather in April

In April, Karatsu sees average daytime highs of 17°C and overnight lows near 12°C, with 134 mm of rain across 11 wet days and about 12.8 hours of daylight. It is the 7th-warmest and 6th-wettest month of the year here.

Highs climb over the month, from about 15°C in the first days to 19°C by the end. The sky is clear or mostly clear about 35% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 18 min at the start of April to 13 h 18 min by month's end. Set against the rest of the year, April is Karatsu's 4th-clearest and 8th-windiest month. For the whole year in context, see Karatsu's year-round climate.

Daytime high
17°
7th warmest
Overnight low
12°
5th coldest
Rainfall
134 mm
11 wet days
Daylight
12 h 48 min
5:55 AM – 6:45 PM
Cloud cover
59%
4th clearest
Wind
13 km/h
8th windiest
Solar energy
5.06 kWh/m²
Travel score
5.3
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 April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 15°C in the first days to 19°C by the end.

A typical April day in Karatsu reaches about 17°C in the afternoon and slips back to 12°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 20°C. Set against its neighbours, April runs about 4°C warmer than March and about 4°C cooler than May.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11510
21510
31511
41511
51611
61611
71611
81611
91611
101611
111612
121712
131712
141712
151712
161712
171712
181713
191813
201813
211813
221813
231813
241813
251914
261914
271914
281914
291914
301914

How April really feels in Karatsu

Once humidity and wind are folded in, April 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

April 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 April compares with the rest of the year at a glance. April is the 7th-warmest and 6th-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 April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 12% of April, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14753
24753
34654
44555
54654
64654
74555
84555
94555
104555
114555
124555
134555
144555
154555
164555
174654
184654
194654
204753
214753
224852
234852
244753
254753
264753
274852
284753
294753
304753

Chance of precipitation in April

Any precipitation

Karatsu gets around 134 mm of rain over 11 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 36% and peaks near 38% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
136
236
336
436
536
636
736
836
936
1037
1137
1237
1337
1438
1538
1638
1738
1838
1937
2037
2137
2237
2337
2436
2536
2636
2735
2835
2934
3034

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, April lands in the dry band about 77% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
191810
291810
390910
4891010
5891010
6871120
7871120
8861220
9861220
10851320
11851320
12841420
13821530
14811630
15801730
16801730
17781840
18771940
19762040
20742150
21722350
22692461
23672661
24652771
25622981
26603091
27593191
285732101
295433112
305333122

Wind in April

Winds average 13 km/h in April.

Across April, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 18 min at the start of April to 13 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over April. Sunrise moves from 6:15 AM to 5:39 AM, and sunset from 6:34 PM to 6:56 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.36:156:34
212.36:146:35
312.46:136:36
412.46:116:36
512.56:106:37
612.56:096:38
712.56:076:39
812.66:066:39
912.66:056:40
1012.66:036:41
1112.76:026:41
1212.76:016:42
1312.75:596:43
1412.85:586:44
1512.85:576:44
1612.85:556:45
1712.95:546:46
1812.95:536:47
1912.95:526:47
2013.05:506:48
2113.05:496:49
2213.05:486:50
2313.15:476:51
2413.15:466:51
2513.15:456:52
2613.25:436:53
2713.25:426:54
2813.25:416:54
2913.35:406:55
3013.35:396:56

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 5.06 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 — April's 5.06 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.8Bright
44.8Bright
54.8Bright
64.9Bright
74.9Bright
84.9Bright
94.9Bright
104.9Bright
115.0Bright
125.0Bright
135.0Bright
145.0Bright
155.0Bright
165.0Bright
175.1Bright
185.1Bright
195.1Bright
205.1Bright
215.1Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.3Bright
295.3Bright
305.3Bright
Planning a trip in April

Hazard calendar for Karatsu

In seasonPeak

In April, 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 April a good time to visit Karatsu?

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

5.3
Sightseeing
6th-best month of the year
1.4
Beach & pool
7th-best month of the year

April is a reasonable time to visit Karatsu for sightseeing.

What to pack for Karatsu in April

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

In April, Karatsu sees daytime highs around 17°C and nights near 12°C. Worth packing: rain gear and sun protection. About 11 days see rain.

rain gearsun protection

Sea temperature near Karatsu in April

The nearest coast averages about 16°C in April — 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 April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 8 — enough to warrant sun protection. 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 April

GoodModeratePoorUnhealthyVery unhealthy

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