Niihama weather in August

In August, Niihama sees average daytime highs of 29°C and overnight lows near 24°C, with 151 mm of rain across 13.8 wet days and about 13.3 hours of daylight. It is the 1st-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 31% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 13 h 42 min at the start of August to 12 h 48 min by month's end. Set against the rest of the year, August is Niihama's 6th-clearest and 11th-windiest month. For the whole year in context, see Niihama's year-round climate.

Daytime high
29°
1st warmest
Overnight low
24°
12th coldest
Rainfall
151 mm
13.8 wet days
Daylight
13 h 18 min
5:33 AM – 6:49 PM
Cloud cover
60%
6th clearest
Wind
8 km/h
11th windiest
Solar energy
5.28 kWh/m²
Travel score
5.0
out of 10

Niihama is city in Ehime Prefecture, Japan.

Density
525/km²
people per km²
Founded
1937

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 29°C through the month.

A typical August day in Niihama reaches about 29°C in the afternoon and slips back to 24°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 31°C. Set against its neighbours, August runs about 1°C warmer than July and about 3°C warmer than September.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12925
22925
32925
42925
52925
62925
72925
82925
92925
102925
112925
122925
132925
142925
152925
162925
172924
182924
192924
202924
212924
222924
232924
242924
252924
262924
272824
282824
292824
302823
312823

How August really feels in Niihama

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.

Niihama weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7813.53.4101.1
Feb / 8412.13.210.71.5
Mar12° / 12213.4111.72.9
Apr17° / 10°13411.60.112.85.1
May21° / 15°15811.2013.76.3
Jun24° / 19°24915.1014.25.7
Jul28° / 23°22815.60145.1
Aug29° / 24°15113.8013.35.0
Sep26° / 21°21614.1012.26.0
Oct21° / 16°16611011.16.4
Nov15° / 10°909.9010.24.8
Dec10° / 9012.81.69.82.3

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 17% of August, with mostly cloudy or overcast conditions the remaining 52%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14951
25050
34951
44951
54951
65050
75050
85050
94951
105050
114951
124951
134852
144852
154753
164753
174852
184852
194852
204852
214852
224753
234852
244852
254753
264852
274852
284753
294753
304753
314654

Chance of precipitation in August

Any precipitation

Niihama gets around 151 mm of rain over 13.8 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 50% on the wettest days.

0%20%40%60%151015202531
Rain chance (%)
144
244
344
443
543
643
743
843
943
1043
1144
1244
1344
1444
1544
1644
1744
1845
1945
2045
2145
2246
2346
2446
2547
2647
2748
2848
2949
3049
3150

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 76% of days. Sticky, muggy-or-worse air turns up on roughly 97% of them.

0%25%50%75%100%151015202531
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10168112
20058213
30058213
40058213
50058213
60058213
70058213
80068113
90068113
100068113
110168112
120178012
130178012
140187912
151197811
1611107711
1711107711
1812117610
191213759
201214749
211315738
221316737
231417717
241418716
251519705
261520695
271621684
281723663
291724653
301825642
311927612

Wind in August

Winds average 8 km/h in August.

Across August, daily wind ranges from about 7 km/h on the calmest days to 8 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
108calm
118calm
128calm
138calm
148calm
158calm
168calm
178calm
188calm
198calm
208calm
218calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm
318calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 42 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 54 minutes over August. Sunrise moves from 5:22 AM to 5:44 AM, and sunset from 7:04 PM to 6:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:227:04
213.75:227:03
313.75:237:02
413.65:247:01
513.65:247:01
613.65:257:00
713.55:266:59
813.55:276:58
913.55:276:57
1013.55:286:56
1113.45:296:55
1213.45:306:54
1313.45:306:52
1413.35:316:51
1513.35:326:50
1613.35:336:49
1713.25:336:48
1813.25:346:47
1913.25:356:46
2013.15:366:44
2113.15:366:43
2213.15:376:42
2313.05:386:41
2413.05:386:39
2513.05:396:38
2612.95:406:37
2712.95:416:35
2812.95:416:34
2912.85:426:33
3012.85:436:31
3112.85:446:30

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.28 kWh/m².

For context, solar energy here swings from a low near 2.35 kWh/m² to a high of 5.61 kWh/m² in May across the year — August's 5.28 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.6Bright
25.6Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.5Bright
85.5Bright
95.5Bright
105.4Bright
115.4Bright
125.4Bright
135.3Bright
145.3Bright
155.3Bright
165.3Bright
175.3Bright
185.2Bright
195.2Bright
205.2Bright
215.2Bright
225.1Bright
235.1Bright
245.1Bright
255.0Bright
265.0Bright
275.0Bright
284.9Bright
294.9Bright
304.8Bright
314.8Bright
Planning a trip in August

Hazard calendar for Niihama

In seasonPeak

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

Niihama 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 Niihama?

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

5.0
Sightseeing
7th-best month of the year
6.3
Beach & pool
1st-best month of the year

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

What to pack for Niihama in August

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

In August, Niihama sees daytime highs around 29°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 14 days see rain.

light clothesrain gearsun protection

Sea temperature near Niihama in August

The nearest coast averages about 28°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 19 km away) is warmest in August at about 28°C and coldest in February near 13°C.

It's comfortable for a long swim from Jun 3 to Nov 13 — about 5.4 months when the water holds above 20°C.

10°15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar13Bracing
Apr15Cool
May18Cool
Jun22Refreshing
Jul25Warm
Aug28Warm
Sep27Warm
Oct24Refreshing
Nov20Cool
Dec17Cool

UV index in Niihama in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Niihama peaks around July 12 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 — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highModerateJul 12UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul10Extreme
Aug9Very high
Sep10Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Niihama 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 Niihama is worst in April — around 22 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (October, 11 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodApr 1321 µg/m³Oct 1311 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb16Moderate
Mar20Moderate
Apr22Moderate
May19Moderate
Jun16Moderate
Jul13Moderate
Aug12Moderate
Sep11Good
Oct11Good
Nov12Good
Dec11Good
Location & terrain

Where is Niihama?

Niihama sits at 34.0°N, 133.3°E, 13 m above sea level, in Japan. The nearest listed city is Saijō, 12 km away.

Topography around Niihama

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

Within 3 km, the terrain around Niihama has only modest variations in elevation — a maximum elevation change of 239 m around an average of 31 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,850 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,946 m.

The land around Niihama is covered by artificial surfaces (61%) and trees (22%) within 3 km, water (46%) and trees (41%) within 16 km, and trees (60%) and water (31%) within 80 km.

3 km
239 m
16 km
1,850 m
80 km
1,946 m
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Saijō 12 km · Shikokuchūō 23 km · Kawanoechō 26 km · Imabari 31 km · Kan’onjichō 36 km · Innoshima 38 km · Tōon 43 km · Mitoyo 44 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 Niihama (33.9605°, 133.3052°, elevation 13 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).