Unzen weather in May

In May, Unzen sees average daytime highs of 24°C and overnight lows near 16°C, with 182 mm of rain across 11.1 wet days and about 13.7 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.

Highs climb over the month, from about 23°C in the first days to 25°C by the end. The sky is clear or mostly clear about 27% 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 Unzen's 10th-clearest and 11th-windiest month. For the whole year in context, see Unzen's year-round climate.

Daytime high
24°
5th warmest
Overnight low
16°
7th coldest
Rainfall
182 mm
11.1 wet days
Daylight
13 h 42 min
5:25 AM – 7:06 PM
Cloud cover
66%
10th clearest
Wind
8 km/h
11th windiest
Solar energy
5.28 kWh/m²
Travel score
6.6
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 23°C in the first days to 25°C by the end.

A typical May day in Unzen reaches about 24°C in the afternoon and slips back to 16°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 21°C and 27°C. Set against its neighbours, May runs about 4°C warmer than April and about 3°C cooler than June.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12214
22315
32315
42315
52315
62315
72315
82315
92316
102416
112416
122416
132416
142416
152416
162416
172416
182417
192517
202517
212517
222517
232517
242517
252517
262518
272518
282518
292618
302618
312618

How May really feels in Unzen

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.

Unzen weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan11° / 707.710.12.7
Feb12° / 88910.83.2
Mar15° / 13411.611.84.6
Apr20° / 12°15110.912.86.1
May24° / 16°18211.113.76.6
Jun27° / 21°4291714.15.2
Jul30° / 24°34818.513.93.7
Aug32° / 25°17914.513.23.5
Sep29° / 22°20312.412.25.3
Oct24° / 17°1127.911.27.3
Nov18° / 12°1028.410.36.2
Dec13° / 817.69.93.9

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 11% of May, with mostly cloudy or overcast conditions the remaining 61%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14258
24159
34159
44060
54159
64159
74060
84060
93961
103961
113961
123961
133862
143862
153961
163961
173961
183961
193862
203862
213862
223862
233961
243763
253763
263763
273763
283664
293664
303565
313466

Chance of precipitation in May

Any precipitation

Unzen gets around 182 mm of rain over 11.1 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 36% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
136
236
336
436
536
636
736
837
937
1037
1137
1236
1336
1436
1536
1635
1735
1835
1935
2035
2135
2235
2335
2435
2535
2635
2735
2836
2936
3037
3137

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 32% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
149281671
247291671
346291771
444301871
542301981
641302081
739312181
838312181
937322281
1036322382
1134332382
1233332482
1332342482
1431342582
1530352582
1628352691
1727362791
1826362891
1925362991
20233630101
21223631101
22213532101
23203533111
24183434121
25173435131
26163336141
27153237151
28133138171
29122938192
30112839202
31102739222

Wind in May

Winds average 8 km/h in May.

Across May, daily wind ranges from about 7 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
19calm
29calm
39calm
49calm
59calm
69calm
79calm
89calm
99calm
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
297calm
307calm
317calm

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 6:55 PM to 7:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.35:386:55
213.35:376:55
313.35:366:56
413.45:356:57
513.45:346:58
613.45:336:58
713.45:326:59
813.55:317:00
913.55:307:01
1013.55:297:01
1113.65:297:02
1213.65:287:03
1313.65:277:03
1413.65:267:04
1513.75:267:05
1613.75:257:06
1713.75:247:06
1813.75:237:07
1913.75:237:08
2013.85:227:09
2113.85:227:09
2213.85:217:10
2313.85:207:11
2413.95:207:11
2513.95:197:12
2613.95:197:13
2713.95:197:13
2813.95:187:14
2913.95:187:15
3014.05:177:15
3114.05:177:16

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.28 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.2 kWh/m² to a high of 5.28 kWh/m² in May across the year — May's 5.28 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.2Bright
25.2Bright
35.2Bright
45.2Bright
55.2Bright
65.2Bright
75.2Bright
85.2Bright
95.2Bright
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
235.3Bright
245.3Bright
255.3Bright
265.3Bright
275.3Bright
285.3Bright
295.3Bright
305.2Bright
315.2Bright
Planning a trip in May

Hazard calendar for Unzen

In seasonPeak

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

Unzen sits in the Pacific typhoon belt; the season peaks July–October.

Unzen's rainy season runs June–July, 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 Unzen?

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

6.6
Sightseeing
2nd-best month of the year
5.6
Beach & pool
4th-best month of the year

May is a reasonable time to visit Unzen for sightseeing.

What to pack for Unzen in May

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

In May, Unzen sees daytime highs around 24°C and nights near 16°C. Worth packing: light clothes, rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Unzen in May

The nearest coast averages about 19°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 17 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 May 27 to Nov 14 — about 5.7 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan15Bracing
Feb14Bracing
Mar14Bracing
Apr16Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov20Cool
Dec17Cool

UV index in Unzen in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May 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 Unzen peaks around July 13 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highVery highModerateJul 13UV 10Dec 21UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr8Very high
May8Very high
Jun10Very high
Jul10Extreme
Aug9Very high
Sep10Very high
Oct7High
Nov4Moderate
Dec3Moderate

Air quality in Unzen 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 Unzen is worst in March — around 25 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (July, 13 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 2325 µg/m³Jul 2114 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb20Moderate
Mar25Moderate
Apr25Moderate
May23Moderate
Jun19Moderate
Jul13Moderate
Aug15Moderate
Sep14Moderate
Oct14Moderate
Nov16Moderate
Dec15Moderate
Location & terrain

Where is Unzen?

Unzen sits at 32.8°N, 130.2°E, 546 m above sea level, in Japan. The nearest listed city is Minamishimabara, 11 km away.

Topography around Unzen

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

Within 3 km, the terrain around Unzen has large variations in elevation — a maximum elevation change of 954 m around an average of 559 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,450 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,724 m.

The land around Unzen is covered by trees (96%) within 3 km, water (42%) and trees (37%) within 16 km, and trees (46%) and water (39%) within 80 km.

3 km
954 m
16 km
1,450 m
80 km
1,724 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Minamishimabara 11 km · Shimabara 11 km · Isahaya 21 km · Nagasu 26 km · Ōyanomachi-noboritate 26 km · Arao 30 km · Ōmura 32 km · Nagasaki 34 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 Unzen (32.7711°, 130.2484°, elevation 546 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).