Arai weather in April

In April, Arai sees average daytime highs of 13°C and overnight lows near 4°C, with 117 mm of precipitation across 14.8 wet days and about 12.9 hours of daylight. It is the 7th-warmest and 12th-wettest month of the year here.

Highs climb over the month, from about 10°C in the first days to 17°C by the end. The sky is clear or mostly clear about 28% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 24 min at the start of April to 13 h 30 min by month's end. Set against the rest of the year, April is Arai's 1st-clearest and 5th-windiest month. For the whole year in context, see Arai's year-round climate.

Daytime high
13°
7th warmest
Overnight low
5th coldest
Precipitation
117 mm
14.8 wet days
Daylight
12 h 54 min
5:19 AM – 6:16 PM
Cloud cover
62%
1st clearest
Wind
8 km/h
5th windiest
Solar energy
5.29 kWh/m²
Travel score
3.4
out of 10

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 10°C in the first days to 17°C by the end.

A typical April day in Arai reaches about 13°C in the afternoon and slips back to 4°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 8°C and 19°C. Set against its neighbours, April runs about 7°C warmer than March and about 6°C cooler than May.

10°20°151015202530
Avg high (°C)Avg low (°C)
1101
2102
3102
4102
5112
6112
7112
8113
9123
10123
11123
12123
13134
14134
15134
16144
17144
18145
19145
20155
21155
22156
23156
24166
25166
26167
27167
28177
29177
30177

How April really feels in Arai

Once humidity and wind are folded in, April averages 0 days that feel above 32°C and 6 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
6
wind chill below the day's low

The story in April is cold — wind chill drags the overnight "feels like" below the raw low.

Arai weather by month

How April compares with the rest of the year at a glance. April is the 7th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -3°24225.423.59.70.0
Feb / -3°17920.918.410.60.0
Mar / -1°1622013.311.70.6
Apr13° / 11714.82.712.93.4
May19° / 10°130140145.6
Jun23° / 16°16616.5014.55.4
Jul26° / 20°24921.1014.34.8
Aug28° / 21°19119.7013.44.8
Sep24° / 17°20417.2012.35.4
Oct18° / 11°18816.40114.9
Nov12° / 16618.23.4102.5
Dec / -1°2272315.69.50.3

Cloud cover in April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% of the time in April, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of April, with mostly cloudy or overcast conditions the remaining 58%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14159
24258
34258
44159
54258
64357
74357
84357
94357
104258
114357
124357
134357
144258
154258
164159
174159
184060
194159
204159
214060
224159
234159
244159
254060
264159
274159
284159
294258
304258

Chance of precipitation in April

Any precipitationSnow

Arai gets around 117 mm of rain and snow over 14.8 wet days in April, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 50% and peaks near 56% on the wettest days, and about 3 days bring snow. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)Snow chance (%)
15624
25623
35522
45520
55419
65418
75317
85316
95215
105214
115112
125111
135011
145010
15499
16498
17497
18486
19485
20474
21474
22473
23463
24462
25462
26461
27461
28451
29451
30451

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)
11000
21000
31000
41000
51000
61000
71000
81000
91000
101000
111000
121000
131000
141000
151000
161000
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27982
28982
29982
30973

Wind in April

Winds average 8 km/h in April.

Across April, daily wind ranges from about 8 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 24 min at the start of April to 13 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 66 minutes over April. Sunrise moves from 5:41 AM to 5:01 AM, and sunset from 6:02 PM to 6:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:416:02
212.45:406:03
312.45:386:04
412.55:376:05
512.55:356:06
612.65:346:07
712.65:326:08
812.65:316:09
912.75:296:09
1012.75:286:10
1112.85:266:11
1212.85:256:12
1312.85:236:13
1412.95:226:14
1512.95:206:15
1612.95:196:16
1713.05:186:17
1813.05:166:18
1913.15:156:18
2013.15:136:19
2113.15:126:20
2213.25:116:21
2313.25:096:22
2413.25:086:23
2513.35:076:24
2613.35:056:25
2713.45:046:26
2813.45:036:27
2913.45:026:27
3013.55:016:28

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 5.29 kWh/m².

For context, solar energy here swings from a low near 2.02 kWh/m² to a high of 5.68 kWh/m² in May across the year — April's 5.29 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.0Bright
45.0Bright
55.1Bright
65.1Bright
75.1Bright
85.2Bright
95.2Bright
105.2Bright
115.2Bright
125.2Bright
135.3Bright
145.3Bright
155.3Bright
165.3Bright
175.3Bright
185.3Bright
195.3Bright
205.3Bright
215.4Bright
225.4Bright
235.4Bright
245.4Bright
255.4Bright
265.5Bright
275.5Bright
285.5Bright
295.5Bright
305.5Bright
Planning a trip in April

Hazard calendar for Arai

In seasonPeak

In April, Arai sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.

Arai 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

Is April a good time to visit Arai?

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

3.4
Sightseeing
7th-best month of the year
0.2
Beach & pool
7th-best month of the year

April is a weaker month for outdoor sightseeing in Arai.

What to pack for Arai in April

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

In April, Arai sees daytime highs around 13°C and nights near 4°C. Pack rain gear. Worth having: a warm layer and sun protection. About 15 days see rain.

rain geara warm layersun protection

Sea temperature near Arai in April

The nearest coast averages about 11°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 16 km away) is warmest in August at about 27°C and coldest in March near 10°C.

It's comfortable for a long swim from Jun 20 to Nov 1 — about 4.4 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb11Bracing
Mar10Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug27Warm
Sep25Warm
Oct22Refreshing
Nov19Cool
Dec15Cool

UV index in Arai in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Arai peaks around August 12 at about 10 (very high) — 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 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateAug 12UV 10Jan 1UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar4Moderate
Apr7High
May8Very high
Jun9Very high
Jul9Very high
Aug10Very high
Sep9Very high
Oct5High
Nov3Moderate
Dec2Moderate

Air quality in Arai 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 Arai is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1721 µg/m³Dec 1510 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar20Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug13Moderate
Sep12Good
Oct11Good
Nov11Good
Dec10Good
Location & terrain

Where is Arai?

Arai sits at 37.0°N, 138.2°E, 175 m above sea level, in Japan. The nearest listed city is Myoko, 4.0 km away.

Topography around Arai

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

Within 3 km, the terrain around Arai has significant variations in elevation — a maximum elevation change of 416 m around an average of 193 m above sea level; within 16 km, extreme variations in elevation — a maximum elevation change of 2,437 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,978 m.

The land around Arai is covered by trees (52%) and cropland (30%) within 3 km, trees (79%) within 16 km, and trees (60%) and water (29%) within 80 km.

3 km
416 m
16 km
2,437 m
80 km
2,978 m
treesgrasslandcroplandartificial surfacesbare terrainwater
April weather nearby: Myoko 4.0 km · Jōetsu 16 km · Iiyama 21 km · Nakano 31 km · Itoigawa 34 km · Nagano 39 km · Suzaka 40 km · Kashiwazaki 50 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 Arai (37.0006°, 138.2259°, elevation 175 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).