Itoigawa weather in April

In April, Itoigawa sees average daytime highs of 11°C and overnight lows near 6°C, with 143 mm of precipitation across 14.8 wet days and about 12.9 hours of daylight. It is the 8th-warmest and 11th-wettest month of the year here.

Highs climb over the month, from about 9°C in the first days to 14°C by the end. The sky is clear or mostly clear about 30% 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 Itoigawa's 1st-clearest and 6th-windiest month. For the whole year in context, see Itoigawa's year-round climate.

Daytime high
11°
8th warmest
Overnight low
5th coldest
Precipitation
143 mm
14.8 wet days
Daylight
12 h 54 min
5:20 AM – 6:17 PM
Cloud cover
61%
1st clearest
Wind
9 km/h
6th windiest
Solar energy
5.26 kWh/m²
Travel score
2.6
out of 10

Itoigawa is city in Niigata prefecture, Japan.

Density
55/km²
people per km²
Founded
1954

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 9°C in the first days to 14°C by the end.

A typical April day in Itoigawa reaches about 11°C in the afternoon and slips back to 6°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 7°C and 16°C. Set against its neighbours, April runs about 5°C warmer than March and about 6°C cooler than May.

10°15°20°151015202530
Avg high (°C)Avg low (°C)
183
293
394
494
594
694
7104
8104
9105
10105
11105
12115
13115
14116
15116
16116
17126
18126
19127
20127
21137
22137
23137
24138
25138
26148
27148
28149
29149
30159

How April really feels in Itoigawa

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.

Itoigawa weather by month

How April compares with the rest of the year at a glance. April is the 8th-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -0°28826.322.89.70.0
Feb / -1°21921.818.710.60.0
Mar / 20020.512.911.70.4
Apr11° / 14314.82.412.92.6
May17° / 12°13914.20144.9
Jun21° / 17°17314.3014.55.5
Jul25° / 21°25418.8014.35.3
Aug27° / 23°19718.1013.45.3
Sep23° / 19°23518.2012.35.3
Oct18° / 14°21617.30114.7
Nov12° / 21319.12.4102.5
Dec / 27424.315.19.50.4

Cloud cover in April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% 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 56%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14258
24357
34357
44456
54456
64357
74555
84555
94555
104456
114456
124555
134456
144456
154456
164357
174357
184357
194357
204357
214357
224456
234357
244357
254456
264357
274456
284456
294456
304456

Chance of precipitation in April

Any precipitationSnow

Itoigawa gets around 143 mm of rain and snow over 14.8 wet days in April. 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 57% on the wettest days, and about 2 days bring snow. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)Snow chance (%)
15723
25621
35620
45519
55518
65517
75415
85414
95313
105212
115211
125110
13519
14508
15507
16496
17495
18484
19483
20473
21462
22462
23462
24451
25451
26451
27451
28441
29440
30440

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
26982
27982
28982
29982
30973

Wind in April

Winds average 9 km/h in April.

Across April, daily wind ranges from about 9 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

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 5:43 AM to 5:02 AM, and sunset from 6:04 PM to 6:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:436:04
212.45:416:05
312.45:406:06
412.55:386:07
512.55:376:07
612.65:356:08
712.65:346:09
812.65:326:10
912.75:316:11
1012.75:296:12
1112.85:286:13
1212.85:266:14
1312.85:256:15
1412.95:236:15
1512.95:226:16
1612.95:206:17
1713.05:196:18
1813.05:186:19
1913.15:166:20
2013.15:156:21
2113.15:136:22
2213.25:126:23
2313.25:116:24
2413.25:096:24
2513.35:086:25
2613.35:076:26
2713.45:066:27
2813.45:046:28
2913.45:036:29
3013.55:026:30

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 5.26 kWh/m².

For context, solar energy here swings from a low near 1.88 kWh/m² to a high of 5.67 kWh/m² in May across the year — April's 5.26 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.9Bright
45.0Bright
55.0Bright
65.0Bright
75.1Bright
85.1Bright
95.1Bright
105.2Bright
115.2Bright
125.2Bright
135.2Bright
145.3Bright
155.3Bright
165.3Bright
175.3Bright
185.3Bright
195.3Bright
205.3Bright
215.3Bright
225.3Bright
235.4Bright
245.4Bright
255.4Bright
265.4Bright
275.4Bright
285.5Bright
295.5Bright
305.5Bright
Planning a trip in April

Hazard calendar for Itoigawa

In seasonPeak

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

Itoigawa 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 Itoigawa?

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

2.6
Sightseeing
7th-best month of the year
0.0
Beach & pool
8th-best month of the year

April is a weaker month for outdoor sightseeing in Itoigawa.

What to pack for Itoigawa in April

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

In April, Itoigawa sees daytime highs around 11°C and nights near 6°C. Pack a warm layer and rain gear. Worth having: sun protection. About 15 days see rain.

a warm layerrain gearsun protection

Sea temperature near Itoigawa 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 offshore 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 Itoigawa in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Itoigawa peaks around August 12 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 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 10Dec 20UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul10Very high
Aug10Very high
Sep9Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Itoigawa 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 Itoigawa 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 Itoigawa?

Itoigawa sits at 37.0°N, 137.8°E, 15 m above sea level, in Japan. The nearest listed city is Nyūzen, 33 km away.

Topography around Itoigawa

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

Within 3 km, the terrain around Itoigawa has significant variations in elevation — a maximum elevation change of 312 m around an average of 44 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,586 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,069 m.

The land around Itoigawa is covered by trees (35%), water (30%) and artificial surfaces (24%) within 3 km, trees (50%) and water (45%) within 16 km, and trees (49%) and water (40%) within 80 km.

3 km
312 m
16 km
1,586 m
80 km
3,069 m
treesgrasslandcroplandartificial surfacesbare terrainwater
April weather nearby: Nyūzen 33 km · Arai 34 km · Myoko 36 km · Jōetsu 37 km · Kurobe-shi 38 km · Uozu 48 km · Iiyama 50 km · Nagano 52 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 Itoigawa (37.0333°, 137.85°, elevation 15 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).