Iwaki weather in May

In May, Iwaki sees average daytime highs of 17°C and overnight lows near 13°C, with 145 mm of rain across 12 wet days and about 14 hours of daylight. It is the 6th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 16°C in the first days to 18°C by the end. The sky is clear or mostly clear about 25% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 30 min at the start of May to 14 h 18 min by month's end. Set against the rest of the year, May is Iwaki's 9th-clearest and 7th-windiest month. For the whole year in context, see Iwaki's year-round climate.

Daytime high
17°
6th warmest
Overnight low
13°
7th coldest
Rainfall
145 mm
12 wet days
Daylight
14 hours
4:33 AM – 6:32 PM
Cloud cover
66%
9th clearest
Wind
15 km/h
7th windiest
Solar energy
5.47 kWh/m²
Travel score
5.1
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 16°C in the first days to 18°C by the end.

A typical May day in Iwaki reaches about 17°C in the afternoon and slips back to 13°C overnight — a 4°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, May runs about 3°C warmer than April and about 3°C cooler than June.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
11511
21612
31612
41612
51612
61612
71612
81612
91612
101613
111613
121713
131713
141713
151713
161713
171713
181713
191714
201714
211714
221714
231814
241814
251814
261814
271815
281815
291815
301815
311815

How May really feels in Iwaki

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.

Iwaki 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 / 7181.59.71.1
Feb / 6881.910.61.1
Mar10° / 12512.1111.72.1
Apr13° / 13411.90.212.93.6
May17° / 13°145120145.1
Jun20° / 17°14713.7014.55.4
Jul23° / 20°17514.5014.35.9
Aug25° / 22°12611.8013.46.5
Sep23° / 20°19214.1012.35.9
Oct19° / 15°22313.40115.6
Nov14° / 10°1119.80104.4
Dec10° / 738.60.29.52.3

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 14% of May, with mostly cloudy or overcast conditions the remaining 60%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14456
24456
34456
44456
54159
64159
74159
84060
93961
103961
113961
123961
133862
143862
153862
163862
173862
183961
193961
203862
213862
223961
234060
243961
253961
263961
273961
283862
293862
303862
313763

Chance of precipitation in May

Any precipitation

Iwaki gets around 145 mm of rain over 12 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 38% and peaks near 39% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
337
437
537
637
737
838
938
1038
1138
1238
1339
1439
1539
1639
1739
1839
1939
2039
2139
2239
2339
2438
2538
2638
2738
2837
2937
3037
3137

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 58% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1801910
2792010
3782110
4772210
5762310
6742510
7722620
8722620
9712720
10702820
11682930
12682930
13663040
14653140
15633340
16613450
17593560
18573760
19553870
20533980
21514090
224841100
234643110
244344130
254145140
263946150
273647170
283448180
293248200
302948220
312748241

Wind in May

Winds average 15 km/h in May.

Across May, daily wind ranges from about 14 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze
3114light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 30 min at the start of May to 14 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 48 minutes over May. Sunrise moves from 4:49 AM to 4:24 AM, and sunset from 6:19 PM to 6:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.54:496:19
213.54:476:20
313.64:466:21
413.64:456:21
513.64:446:22
613.74:436:23
713.74:426:24
813.74:416:25
913.84:406:26
1013.84:396:27
1113.84:386:28
1213.94:376:29
1313.94:366:29
1413.94:356:30
1513.94:346:31
1614.04:336:32
1714.04:336:33
1814.04:326:34
1914.14:316:35
2014.14:306:35
2114.14:306:36
2214.14:296:37
2314.24:286:38
2414.24:286:39
2514.24:276:39
2614.24:266:40
2714.34:266:41
2814.34:256:42
2914.34:256:42
3014.34:246:43
3114.34:246:44

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.47 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.32 kWh/m² to a high of 5.47 kWh/m² in May across the year — May's 5.47 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.4Bright
45.4Bright
55.4Bright
65.4Bright
75.4Bright
85.4Bright
95.4Bright
105.4Bright
115.4Bright
125.4Bright
135.4Bright
145.4Bright
155.4Bright
165.4Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.5Bright
225.5Bright
235.5Bright
245.6Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.6Bright
305.6Bright
315.6Bright
Planning a trip in May

Hazard calendar for Iwaki

In seasonPeak

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

Iwaki 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 May a good time to visit Iwaki?

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

5.1
Sightseeing
6th-best month of the year
1.1
Beach & pool
6th-best month of the year

May is a reasonable time to visit Iwaki for sightseeing.

What to pack for Iwaki in May

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

In May, Iwaki sees daytime highs around 17°C and nights near 13°C. Worth packing: a warm layer, rain gear and sun protection. About 12 days see rain.

a warm layerrain gearsun protection

Sea temperature near Iwaki in May

The nearest coast averages about 16°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 19 km away) is warmest in August at about 24°C and coldest in March near 12°C.

It's comfortable for a long swim from Jul 1 to Oct 22 — about 3.7 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb12Bracing
Mar12Bracing
Apr14Bracing
May16Cool
Jun19Cool
Jul21Refreshing
Aug24Refreshing
Sep23Refreshing
Oct20Refreshing
Nov18Cool
Dec16Cool

UV index in Iwaki 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 Iwaki peaks around July 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateJul 18UV 9Jan 1UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug9Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Iwaki 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 Iwaki is worst in April — around 19 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 2219 µg/m³Dec 177 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb11Good
Mar17Moderate
Apr19Moderate
May19Moderate
Jun14Moderate
Jul12Moderate
Aug11Good
Sep10Good
Oct10Good
Nov9Good
Dec7Good
Location & terrain

Where is Iwaki?

Iwaki sits at 37.0°N, 140.9°E, 9 m above sea level, in Japan. The nearest listed city is Kitaibaraki, 32 km away.

Topography around Iwaki

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

Within 3 km, the terrain around Iwaki has only modest variations in elevation — a maximum elevation change of 129 m around an average of 35 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 776 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,678 m.

The land around Iwaki is covered by artificial surfaces (46%) and trees (41%) within 3 km, trees (57%) and water (22%) within 16 km, and trees (55%) and water (32%) within 80 km.

3 km
129 m
16 km
776 m
80 km
1,678 m
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Kitaibaraki 32 km · Takahagi 40 km · Ishikawa 40 km · Tamura 49 km · Namie 49 km · Sukagawa 51 km · Funehikimachi-funehiki 52 km · Yabuki 53 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 Iwaki (37.05°, 140.8833°, elevation 9 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).