Aso weather in August

In August, Aso sees average daytime highs of 30°C and overnight lows near 22°C, with 164 mm of rain across 16.3 wet days and about 13.2 hours of daylight. It is the 1st-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 23% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 13 h 36 min at the start of August to 12 h 42 min by month's end. Set against the rest of the year, August is Aso's 9th-clearest and 10th-windiest month. For the whole year in context, see Aso's year-round climate.

Daytime high
30°
1st warmest
Overnight low
22°
12th coldest
Rainfall
164 mm
16.3 wet days
Daylight
13 h 12 min
5:43 AM – 6:57 PM
Cloud cover
65%
9th clearest
Wind
7 km/h
10th windiest
Solar energy
4.76 kWh/m²
Travel score
4.4
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 August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical August day in Aso reaches about 30°C in the afternoon and slips back to 22°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 32°C. Set against its neighbours, August runs about 1°C warmer than July and about 3°C warmer than September.

15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13022
23022
33022
43022
53022
63022
73022
83022
93022
103022
113022
123022
133022
143022
153022
163022
173022
183022
193022
203022
212922
222922
232922
242921
252921
262921
272921
282921
292921
302921
312921

How August really feels in Aso

Once humidity and wind are folded in, August averages 20 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
20
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in August is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Aso weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 5th-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 August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 23% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 19% of August, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14555
24555
34555
44456
54357
64357
74357
84357
94159
104159
114159
124159
134159
144060
154060
164159
174258
184258
194258
204258
214357
224357
234357
244357
254357
264357
274357
284357
294357
304357
314258

Chance of precipitation in August

Any precipitation

Aso gets around 164 mm of rain over 16.3 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 53% and peaks near 54% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
153
253
352
452
552
651
751
851
951
1051
1151
1251
1351
1452
1552
1652
1753
1853
1953
2053
2154
2254
2354
2454
2554
2654
2754
2854
2953
3053
3152

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the oppressive band about 57% of days. Sticky, muggy-or-worse air turns up on roughly 94% of them.

0%25%50%75%100%151015202531
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10133651
20133651
30133651
40133651
50133651
60133651
70133651
80133651
90133651
100133651
110233641
120233641
130233641
140233641
150333631
161333621
171433611
181434601
191534591
201535581
211636561
222737531
232838511
242840491
252941470
2621042450
2731143420
2831244400
2931345380
3041446360
3141546340

Wind in August

Winds average 7 km/h in August.

Across August, 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 August

DaylightNight

Daylight runs from about 13 h 36 min at the start of August to 12 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 54 minutes over August. Sunrise moves from 5:32 AM to 5:53 AM, and sunset from 7:11 PM to 6:38 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:327:11
213.65:337:10
313.65:347:09
413.65:357:09
513.55:357:08
613.55:367:07
713.55:377:06
813.55:377:05
913.45:387:04
1013.45:397:03
1113.45:397:02
1213.35:407:01
1313.35:417:00
1413.35:426:59
1513.35:426:58
1613.25:436:57
1713.25:446:55
1813.25:446:54
1913.15:456:53
2013.15:466:52
2113.15:466:51
2213.05:476:50
2313.05:486:48
2413.05:496:47
2512.95:496:46
2612.95:506:45
2712.95:516:43
2812.85:516:42
2912.85:526:41
3012.85:536:39
3112.75:536:38

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 4.76 kWh/m².

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 — August's 4.76 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.1Bright
45.0Bright
55.0Bright
65.0Bright
75.0Bright
85.0Bright
94.9Bright
104.9Bright
114.9Bright
124.9Bright
134.8Bright
144.8Bright
154.8Bright
164.8Bright
174.7Bright
184.7Bright
194.7Bright
204.7Bright
214.6Bright
224.6Bright
234.6Bright
244.5Bright
254.5Bright
264.5Bright
274.5Bright
284.4Bright
294.4Bright
304.3Bright
314.3Bright
Planning a trip in August

Hazard calendar for Aso

In seasonPeak

In August, 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 August a good time to visit Aso?

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

4.4
Sightseeing
7th-best month of the year
5.9
Beach & pool
2nd-best month of the year

August is a reasonable time to visit Aso for sightseeing.

What to pack for Aso in August

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

In August, Aso sees daytime highs around 30°C and nights near 22°C. Pack light clothes and rain gear. Worth having: sun protection. About 16 days see rain.

light clothesrain gearsun protection

Sea temperature near Aso in August

The nearest coast averages about 27°C in August — 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 August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 10 (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 August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August 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
August 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).