Suwa weather in August

In August, Suwa sees average daytime highs of 27°C and overnight lows near 18°C, with 123 mm of rain across 13.4 wet days and about 13.4 hours of daylight. It is the 1st-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 26°C by the end. The sky is clear or mostly clear about 19% of the time in August, and the air most often feels humid.

Daylight stretches from about 13 h 48 min at the start of August to 12 h 48 min by month's end. Set against the rest of the year, August is Suwa's 9th-clearest and 12th-windiest month. For the whole year in context, see Suwa's year-round climate.

Daytime high
27°
1st warmest
Overnight low
18°
12th coldest
Rainfall
123 mm
13.4 wet days
Daylight
13 h 24 min
5:10 AM – 6:33 PM
Cloud cover
67%
9th clearest
Wind
5 km/h
12th windiest
Solar energy
5.05 kWh/m²
Travel score
5.9
out of 10

Suwa is city in Nagano Prefecture, Japan.

Density
449/km²
people per km²
Founded
1941

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

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 27°C in the first days to 26°C by the end.

A typical August day in Suwa reaches about 27°C in the afternoon and slips back to 18°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 30°C. Set against its neighbours, August runs about 1°C warmer than July and about 4°C warmer than September.

10°15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12719
22719
32719
42719
52719
62719
72719
82719
92719
102719
112719
122719
132719
142719
152718
162718
172718
182718
192718
202718
212718
222718
232618
242618
252618
262618
272618
282617
292617
302617
312617

How August really feels in Suwa

Once humidity and wind are folded in, August 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

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Suwa weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -8°8511.512.49.80.0
Feb / -7°8610.19.510.60.0
Mar / -3°14213.38.911.70.9
Apr14° / 12712.41.912.93.7
May19° / 13312.10.113.95.7
Jun22° / 14°17815.5014.45.4
Jul26° / 18°19817014.25.5
Aug27° / 18°12313.4013.45.9
Sep23° / 15°15912.8012.26.1
Oct17° / 17012.10.111.15.2
Nov11° / 9710.41.710.12.8
Dec / -4°84129.49.60.2

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 19% 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 62%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13763
23862
33862
43862
53862
63862
73862
83862
93862
103862
113763
123862
133763
143763
153763
163862
173862
183862
193961
203961
213961
223961
233961
243862
253862
263961
273961
283961
293862
303763
313763

Chance of precipitation in August

Any precipitation

Suwa gets around 123 mm of rain over 13.4 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 43% and peaks near 45% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
145
245
345
445
544
644
744
844
944
1044
1143
1243
1343
1443
1543
1643
1743
1843
1942
2042
2142
2242
2342
2443
2543
2643
2743
2844
2944
3044
3144

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the humid band about 60% of days. Sticky, muggy-or-worse air turns up on roughly 25% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1086428
2086329
3076330
4076330
5076231
6066331
7166231
8166231
9166231
10176131
11176131
12176131
13186130
14295930
15296029
162106028
172116027
183125926
193135925
203155824
213165922
223175921
234185820
244195918
254215817
264225816
275235715
285245714
296255613
306265612
317265611

Wind in August

Winds average 5 km/h in August, the calmest month.

Across August, daily wind ranges from about 5 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 48 min at the start of August to 12 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 60 minutes over August. Sunrise moves from 4:58 AM to 5:22 AM, and sunset from 6:49 PM to 6:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.84:586:49
213.84:596:48
313.85:006:47
413.85:016:46
513.75:016:45
613.75:026:44
713.75:036:43
813.65:046:42
913.65:056:41
1013.65:056:40
1113.55:066:39
1213.55:076:38
1313.55:086:37
1413.45:096:35
1513.45:096:34
1613.45:106:33
1713.35:116:32
1813.35:126:31
1913.35:136:29
2013.25:146:28
2113.25:146:27
2213.25:156:25
2313.15:166:24
2413.15:176:23
2513.15:186:21
2613.05:186:20
2713.05:196:18
2813.05:206:17
2912.95:216:16
3012.95:226:14
3112.85:226:13

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.05 kWh/m².

For context, solar energy here swings from a low near 2.54 kWh/m² to a high of 5.73 kWh/m² in May across the year — August's 5.05 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.3Bright
65.3Bright
75.3Bright
85.3Bright
95.2Bright
105.2Bright
115.2Bright
125.1Bright
135.1Bright
145.1Bright
155.1Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
204.9Bright
214.9Bright
224.9Bright
234.8Bright
244.8Bright
254.8Bright
264.7Bright
274.7Bright
284.7Bright
294.6Bright
304.6Bright
314.6Bright
Planning a trip in August

Hazard calendar for Suwa

In seasonPeak

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

Suwa 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 August a good time to visit Suwa?

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

5.9
Sightseeing
2nd-best month of the year
5.9
Beach & pool
1st-best month of the year

August is a reasonable time to visit Suwa for sightseeing.

What to pack for Suwa in August

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

In August, Suwa sees daytime highs around 27°C and nights near 18°C. Worth packing: light clothes, rain gear and sun protection. About 13 days see rain.

light clothesrain gearsun protection

UV index in Suwa 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 Suwa peaks around July 14 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJul 14UV 11Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Suwa 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 Suwa is worst in April — around 18 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1918 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb11Good
Mar17Moderate
Apr18Moderate
May17Moderate
Jun16Moderate
Jul13Moderate
Aug12Good
Sep10Good
Oct10Good
Nov9Good
Dec8Good
Location & terrain

Where is Suwa?

Suwa sits at 36.0°N, 138.1°E, 762 m above sea level, in Japan. The nearest listed city is Shimosuwa, 5.0 km away.

Topography around Suwa

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

Within 3 km, the terrain around Suwa has significant variations in elevation — a maximum elevation change of 507 m around an average of 828 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,248 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,057 m.

The land around Suwa is covered by artificial surfaces (34%), trees (27%) and water (22%) within 3 km, trees (76%) within 16 km, and trees (87%) within 80 km.

3 km
507 m
16 km
1,248 m
80 km
3,057 m
treesgrasslandcroplandartificial surfaceswater
August weather nearby: Shimosuwa 5.0 km · Chino 6.0 km · Okaya 6.0 km · Tatsuno 12 km · Shiojiri 15 km · Kinoshita 19 km · Minamiminowa 22 km · Matsumoto 25 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 Suwa (36.038°, 138.1131°, elevation 762 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). 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).