Iwai weather in July

In July, Iwai sees average daytime highs of 27°C and overnight lows near 21°C, with 243 mm of rain across 21.8 wet days and about 14.2 hours of daylight. It is the 2nd-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 26°C in the first days to 28°C by the end. The sky is clear or mostly clear about 12% of the time in July, and the air most often feels oppressive.

Daylight stretches from about 14 h 24 min at the start of July to 13 h 54 min by month's end. Set against the rest of the year, July is Iwai's 11th-clearest and 10th-windiest month. For the whole year in context, see Iwai's year-round climate.

Daytime high
27°
2nd warmest
Overnight low
21°
11th coldest
Rainfall
243 mm
21.8 wet days
Daylight
14 h 12 min
4:43 AM – 6:55 PM
Cloud cover
78%
11th clearest
Wind
6 km/h
10th windiest
Solar energy
4.48 kWh/m²
Travel score
4.5
out of 10

Temperature in July

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 26°C in the first days to 28°C by the end.

A typical July day in Iwai reaches about 27°C in the afternoon and slips back to 21°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 31°C. Set against its neighbours, July runs about 4°C warmer than June and about 1°C cooler than August.

15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12519
22620
32620
42620
52620
62620
72620
82620
92721
102721
112721
122721
132721
142721
152721
162721
172721
182721
192821
202822
212822
222822
232822
242822
252822
262822
272822
282822
292822
302922
312922

How July really feels in Iwai

Once humidity and wind are folded in, July 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

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

Iwai weather by month

How July compares with the rest of the year at a glance. July is the 2nd-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -2°778.54.49.91.0
Feb / -1°759.64.610.61.2
Mar11° / 13915.24.711.72.5
Apr16° / 14614.60.912.94.5
May21° / 13°16615.6013.95.5
Jun23° / 17°22219.5014.44.9
Jul27° / 21°24321.8014.24.5
Aug28° / 22°20521013.44.4
Sep25° / 18°24918.3012.25.2
Oct19° / 13°24216.2011.15.2
Nov14° / 10111.30.210.14.1
Dec10° / 688.31.49.62.2

Cloud cover in July

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 12% of the time in July.

Beyond those clear spells, partly cloudy skies cover about 12% of July, with mostly cloudy or overcast conditions the remaining 76%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11783
21882
31981
41981
52080
62179
72179
82179
92179
102278
112278
122278
132278
142278
152278
162278
172278
182278
192377
202476
212476
222575
232674
242674
252872
262971
272971
283169
293268
303268
313367

Chance of precipitation in July

Any precipitation

Iwai gets around 243 mm of rain over 21.8 wet days in July. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 70% and peaks near 73% on the wettest days.

0%20%40%60%80%151015202531
Rain chance (%)
173
272
372
472
572
672
771
871
971
1071
1171
1271
1371
1471
1570
1670
1770
1870
1970
2070
2169
2269
2369
2469
2569
2669
2768
2868
2968
3068
3168

Humidity in July

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, July lands in the oppressive band about 44% of days. Sticky, muggy-or-worse air turns up on roughly 82% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1162846190
2162646210
3052547220
4052447240
5042247260
6042147280
7032047290
8031946310
9031845331
10031844351
11021743371
12021741391
13021640401
14021638422
15021637442
16021536452
17021434472
18021433492
19021332503
20021231523
21021230533
22021129553
23021029563
24021028573
2501928593
2601827604
2701826614
2801726624
2901725634
3001624654
3101623655

Wind in July

Winds average 6 km/h in July.

Across July, daily wind ranges from about 6 km/h on the calmest days to 6 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in July

DaylightNight

Daylight runs from about 14 h 24 min at the start of July to 13 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 30 minutes over July. Sunrise moves from 4:35 AM to 4:53 AM, and sunset from 6:58 PM to 6:45 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.44:356:58
214.44:356:58
314.44:356:58
414.44:366:58
514.44:366:58
614.34:376:58
714.34:376:58
814.34:386:57
914.34:386:57
1014.34:396:57
1114.34:406:57
1214.34:406:56
1314.34:416:56
1414.24:416:56
1514.24:426:55
1614.24:436:55
1714.24:436:54
1814.24:446:54
1914.14:456:53
2014.14:456:53
2114.14:466:52
2214.14:476:52
2314.14:476:51
2414.04:486:50
2514.04:496:50
2614.04:506:49
2714.04:506:48
2813.94:516:47
2913.94:526:47
3013.94:536:46
3113.94:536:45

Solar energy in July

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in July, about 4.48 kWh/m².

For context, solar energy here swings from a low near 2.39 kWh/m² to a high of 5.06 kWh/m² in May across the year — July's 4.48 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.1Bright
24.2Bright
34.2Bright
44.2Bright
54.2Bright
64.2Bright
74.3Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.4Bright
134.4Bright
144.4Bright
154.4Bright
164.5Bright
174.5Bright
184.5Bright
194.5Bright
204.6Bright
214.6Bright
224.6Bright
234.7Bright
244.7Bright
254.7Bright
264.8Bright
274.8Bright
284.8Bright
294.8Bright
304.8Bright
314.8Bright
Planning a trip in July

Hazard calendar for Iwai

In seasonPeak

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

Iwai 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 July a good time to visit Iwai?

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

4.5
Sightseeing
5th-best month of the year
4.7
Beach & pool
2nd-best month of the year

July is a reasonable time to visit Iwai for sightseeing.

What to pack for Iwai in July

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

In July, Iwai sees daytime highs around 27°C and nights near 21°C. Pack light clothes and rain gear. About 22 days see rain.

light clothesrain gear

Sea temperature near Iwai in July

The nearest coast averages about 23°C in July — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 60 km away) is warmest in August at about 26°C and coldest in February near 13°C.

It's comfortable for a long swim from Jun 7 to Nov 3 — about 4.9 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan14Bracing
Feb13Bracing
Mar13Bracing
Apr15Cool
May18Cool
Jun21Refreshing
Jul23Refreshing
Aug26Warm
Sep25Warm
Oct22Refreshing
Nov19Cool
Dec16Cool

UV index in Iwai in July

LowModerateHighVery highExtreme

Clear-sky midday UV in July 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 Iwai peaks around July 16 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highModerateJul 16UV 10Dec 23UV 2
UV index (midday)Level
Jan2Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May9Very high
Jun9Very high
Jul10Very high
Aug9Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Iwai in July

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where July falls, not just the annual average.

Air quality in Iwai is worst in April — around 26 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (December, 14 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateApr 1426 µg/m³Dec 1814 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb21Moderate
Mar25Moderate
Apr26Moderate
May24Moderate
Jun20Moderate
Jul17Moderate
Aug16Moderate
Sep16Moderate
Oct16Moderate
Nov16Moderate
Dec14Moderate
Location & terrain

Where is Iwai?

Iwai sits at 35.8°N, 139.2°E, 321 m above sea level, in Japan. The nearest listed city is Akiruno, 2.0 km away.

Topography around Iwai

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

Within 3 km, the terrain around Iwai has significant variations in elevation — a maximum elevation change of 387 m around an average of 279 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,339 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,737 m.

The land around Iwai is covered by trees (82%) within 3 km, trees (73%) and artificial surfaces (22%) within 16 km, and trees (48%) and artificial surfaces (27%) within 80 km.

3 km
387 m
16 km
1,339 m
80 km
3,737 m
treesgrasslandcroplandartificial surfacesbare terrainwater
July weather nearby: Akiruno 2.0 km · Itsukaichi 3.0 km · Ōme 4.0 km · Hamura 8.0 km · Fussa 8.0 km · Hakonegasaki 11 km · Hachiōji 13 km · Yokota 14 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 Iwai (35.75°, 139.2333°, elevation 321 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).