Aso weather in May

In May, Aso sees average daytime highs of 23°C and overnight lows near 13°C, with 181 mm of rain across 12.4 wet days and about 13.7 hours of daylight. It is the 5th-warmest and 3rd-wettest month of the year here.

Highs climb over the month, from about 21°C in the first days to 24°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 18 min at the start of May to 14 hours by month's end. Set against the rest of the year, May is Aso's 10th-clearest and 7th-windiest month. For the whole year in context, see Aso's year-round climate.

Daytime high
23°
5th warmest
Overnight low
13°
8th coldest
Rainfall
181 mm
12.4 wet days
Daylight
13 h 42 min
5:21 AM – 7:03 PM
Cloud cover
67%
10th clearest
Wind
7 km/h
7th windiest
Solar energy
5.19 kWh/m²
Travel score
6.3
out of 10

Aso is city in Kumamoto Prefecture, Japan.

Density
72/km²
people per km²
Founded
2005

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 21°C in the first days to 24°C by the end.

A typical May day in Aso reaches about 23°C in the afternoon and slips back to 13°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 19°C and 26°C. Set against its neighbours, May runs about 4°C warmer than April and about 2°C cooler than June.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12111
22111
32111
42111
52211
62212
72212
82212
92212
102212
112212
122212
132213
142313
152313
162313
172313
182313
192313
202313
212313
222314
232314
242314
252414
262414
272414
282414
292415
302415
312415

How May really feels in Aso

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.

Aso weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -1°698.82.810.11.2
Feb / 929.42.110.81.9
Mar13° / 14012.80.911.73.6
Apr18° / 15811.70.112.85.5
May23° / 13°18112.4013.76.3
Jun25° / 18°41318014.15.2
Jul28° / 21°31918.80144.4
Aug30° / 22°16416.3013.24.4
Sep27° / 18°16512.9012.26.0
Oct22° / 12°1027.7011.27.1
Nov16° / 818.1010.35.3
Dec10° / 698.61.39.92.4

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 11% of May, with mostly cloudy or overcast conditions the remaining 64%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24159
34060
44060
53862
63862
73862
83862
93763
103763
113862
123763
133763
143763
153664
163763
173763
183664
193664
203763
213664
223565
233565
243565
253466
263367
273367
283367
293169
303169
313070

Chance of precipitation in May

Any precipitation

Aso gets around 181 mm of rain over 12.4 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 40% and peaks near 41% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
140
240
340
440
540
641
741
841
941
1041
1141
1241
1341
1440
1540
1639
1739
1839
1938
2038
2138
2238
2338
2438
2538
2638
2738
2839
2939
3040
3141

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 60% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1731791
2721792
3711892
47018102
56919102
66819103
76819103
86620113
96620113
106520114
116520114
126520114
136520114
146421114
156421114
166322114
176223114
186124114
196025114
205826124
215727124
225528134
235429134
245230144
255031154
264932154
274733165
284433175
294234185
304035196
313735217

Wind in May

Winds average 7 km/h in May.

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

0246810151015202531
Wind speed (km/h)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
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 5:34 AM to 5:13 AM, and sunset from 6:51 PM to 7:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.35:346:51
213.35:336:52
313.35:326:53
413.45:316:54
513.45:306:54
613.45:296:55
713.55:286:56
813.55:286:57
913.55:276:57
1013.55:266:58
1113.65:256:59
1213.65:247:00
1313.65:237:00
1413.65:237:01
1513.75:227:02
1613.75:217:03
1713.75:207:03
1813.75:207:04
1913.85:197:05
2013.85:197:06
2113.85:187:06
2213.85:177:07
2313.85:177:08
2413.95:167:08
2513.95:167:09
2613.95:157:10
2713.95:157:10
2813.95:147:11
2914.05:147:12
3014.05:147:12
3114.05:137:13

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.19 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 2.33 kWh/m² to a high of 5.19 kWh/m² in May across the year — May's 5.19 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
145.2Bright
155.2Bright
165.2Bright
175.2Bright
185.2Bright
195.2Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.1Bright
295.1Bright
305.0Bright
315.0Bright
Planning a trip in May

Hazard calendar for Aso

In seasonPeak

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

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

Aso'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 Aso?

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

6.3
Sightseeing
2nd-best month of the year
4.7
Beach & pool
6th-best month of the year

May is a reasonable time to visit Aso for sightseeing.

What to pack for Aso in May

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

In May, Aso sees daytime highs around 23°C and nights near 13°C. Worth packing: light clothes, rain gear and sun protection. About 12 days see rain.

light clothesrain gearsun protection

Sea temperature near Aso 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 43 km away) is warmest in August at about 27°C and coldest in February near 13°C.

It's comfortable for a long swim from May 27 to Nov 13 — about 5.6 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar14Bracing
Apr16Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov20Cool
Dec17Cool

UV index in Aso in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Aso peaks around June 23 at about 10 (extreme) — 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 — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJun 23UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar7High
Apr8Very high
May9Very high
Jun11Extreme
Jul10Extreme
Aug10Very high
Sep10Very high
Oct7High
Nov4Moderate
Dec3Moderate

Air quality in Aso 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 Aso is worst in March — around 30 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (September, 14 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateMar 1829 µg/m³Sep 2214 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb20Moderate
Mar30Moderate
Apr24Moderate
May22Moderate
Jun19Moderate
Jul14Moderate
Aug15Moderate
Sep14Moderate
Oct14Moderate
Nov15Moderate
Dec14Moderate
Location & terrain

Where is Aso?

Aso sits at 32.9°N, 131.1°E, 520 m above sea level, in Japan. The nearest listed city is Ōzu, 20 km away.

Topography around Aso

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

Within 3 km, the terrain around Aso has significant variations in elevation — a maximum elevation change of 428 m around an average of 568 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,443 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,757 m.

The land around Aso is covered by cropland (53%) and trees (29%) within 3 km, trees (65%) and cropland (20%) within 16 km, and trees (71%) within 80 km.

3 km
428 m
16 km
1,443 m
80 km
1,757 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Ōzu 20 km · Kikuchi 25 km · Okino 28 km · Kōshi 29 km · Takedamachi 30 km · Shimada 34 km · Mifune 34 km · Kotō 36 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 Aso (32.9373°, 131.0801°, elevation 520 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).