Nagaoka weather in August

In August, Nagaoka sees average daytime highs of 31°C and overnight lows near 23°C, with 146 mm of rain across 14.1 wet days and about 13.4 hours of daylight. It is the 1st-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 31°C in the first days to 30°C by the end. The sky is clear or mostly clear about 27% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 13 h 54 min at the start of August to 12 h 54 min by month's end. Set against the rest of the year, August is Nagaoka's 1st-clearest and 11th-windiest month. For the whole year in context, see Nagaoka's year-round climate.

Daytime high
31°
1st warmest
Overnight low
23°
12th coldest
Rainfall
146 mm
14.1 wet days
Daylight
13 h 30 min
5:05 AM – 6:32 PM
Cloud cover
61%
1st clearest
Wind
7 km/h
11th windiest
Solar energy
5.15 kWh/m²
Travel score
4.1
out of 10

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 31°C in the first days to 30°C by the end.

A typical August day in Nagaoka reaches about 31°C in the afternoon and slips back to 23°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 35°C. Set against its neighbours, August runs about 2°C warmer than July and about 4°C warmer than September.

15°20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
13123
23123
33223
43223
53223
63223
73223
83223
93223
103223
113123
123123
133123
143123
153123
163123
173123
183123
193123
203123
213123
223123
233022
243022
253022
263022
273022
283022
293022
303022
312922

How August really feels in Nagaoka

Once humidity and wind are folded in, August averages 29 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
29
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.

Nagaoka weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -0°1792518.29.70.1
Feb / -0°12620.514.610.60.3
Mar10° / 12619.67.611.71.8
Apr16° / 9414.30.812.94.6
May22° / 12°9411.90146.3
Jun26° / 17°11512.5014.56.1
Jul29° / 22°20716.1014.34.6
Aug31° / 23°14614.1013.44.1
Sep27° / 19°14414012.35.6
Oct20° / 12°14314.80115.7
Nov14° / 14518.20.6103.3
Dec / 18123.7109.50.9

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 27% of the time in August, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 19% of August, with mostly cloudy or overcast conditions the remaining 54%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14456
24555
34654
44654
54555
64555
74654
84654
94654
104753
114654
124753
134753
144555
154753
164753
174654
184654
194852
204852
214852
224753
234753
244753
254753
264654
274555
284555
294456
304456
314456

Chance of precipitation in August

Any precipitation

Nagaoka gets around 146 mm of rain over 14.1 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 45% and peaks near 49% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
138
238
339
439
539
640
741
841
942
1043
1143
1244
1345
1445
1546
1647
1747
1848
1948
2048
2148
2249
2349
2449
2549
2649
2749
2849
2949
3049
3149

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 58% 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 (%)
10223687
20223687
30223678
40223678
50224668
60224668
70224668
80225658
90225658
100325639
110325639
120326629
131326619
141426609
151426609
161526608
171527598
181527598
191628587
201628587
211729567
221730566
231831546
241833535
251934515
2611036494
2711037474
2811139454
2911240433
3021341413
3121442403

Wind in August

Winds average 7 km/h in August.

Across August, daily wind ranges from about 6 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
16calm
26calm
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 54 min at the start of August to 12 h 54 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 4:52 AM to 5:18 AM, and sunset from 6:49 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.94:526:49
213.94:536:48
313.94:546:47
413.94:556:46
513.84:566:45
613.84:566:44
713.84:576:43
813.74:586:42
913.74:596:41
1013.75:006:40
1113.65:016:38
1213.65:026:37
1313.65:036:36
1413.55:036:35
1513.55:046:34
1613.55:056:32
1713.45:066:31
1813.45:076:30
1913.35:086:28
2013.35:096:27
2113.35:096:26
2213.25:106:24
2313.25:116:23
2413.25:126:21
2513.15:136:20
2613.15:146:19
2713.05:156:17
2813.05:166:16
2913.05:166:14
3012.95:176:13
3112.95:186:11

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.15 kWh/m².

For context, solar energy here swings from a low near 1.74 kWh/m² to a high of 5.68 kWh/m² in May across the year — August's 5.15 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.4Bright
85.4Bright
95.4Bright
105.3Bright
115.3Bright
125.3Bright
135.2Bright
145.2Bright
155.2Bright
165.1Bright
175.1Bright
185.1Bright
195.0Bright
205.0Bright
215.0Bright
224.9Bright
234.9Bright
244.9Bright
254.8Bright
264.8Bright
274.8Bright
284.7Bright
294.7Bright
304.6Bright
314.6Bright
Planning a trip in August

Hazard calendar for Nagaoka

In seasonPeak

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

Nagaoka 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 Nagaoka?

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

4.1
Sightseeing
7th-best month of the year
6.0
Beach & pool
1st-best month of the year

August is a reasonable time to visit Nagaoka for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Nagaoka in August

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

In August, Nagaoka sees daytime highs around 31°C and nights near 23°C. Pack light clothes and rain gear. Worth having: sun protection. About 14 days see rain.

light clothesrain gearsun protection

Sea temperature near Nagaoka 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 22 km away) is warmest in August at about 27°C and coldest in March near 10°C.

It's comfortable for a long swim from Jun 21 to Oct 31 — about 4.4 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb11Bracing
Mar10Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug27Warm
Sep25Warm
Oct22Refreshing
Nov18Cool
Dec15Cool

UV index in Nagaoka 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 Nagaoka peaks around August 12 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highModerateAug 12UV 10Dec 22UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun8Very high
Jul9Very high
Aug10Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Nagaoka 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 Nagaoka is worst in April — around 23 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodApr 1723 µg/m³Dec 1610 µg/m³
PM2.5 (µg/m³)Level
Jan12Good
Feb15Moderate
Mar22Moderate
Apr23Moderate
May22Moderate
Jun19Moderate
Jul17Moderate
Aug14Moderate
Sep12Moderate
Oct12Good
Nov11Good
Dec10Good
Location & terrain

Where is Nagaoka?

Nagaoka sits at 37.5°N, 138.8°E, 23 m above sea level, in Japan. The nearest listed city is Mitsuke, 12 km away.

Topography around Nagaoka

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

Within 3 km, the terrain around Nagaoka has only modest variations in elevation — a maximum elevation change of 53 m around an average of 23 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 741 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,314 m.

The land around Nagaoka is covered by artificial surfaces (64%) within 3 km, trees (59%) and cropland (25%) within 16 km, and trees (56%) and water (32%) within 80 km.

3 km
53 m
16 km
741 m
80 km
2,314 m
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Mitsuke 12 km · Tochio-honchō 13 km · Ojiya 17 km · Sanjō 21 km · Tsubame 25 km · Uonuma 25 km · Yoshida-kasugachō 26 km · Kashiwazaki 28 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 Nagaoka (37.45°, 138.85°, elevation 23 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).