Iwata weather in September

In September, Iwata sees average daytime highs of 28°C and overnight lows near 22°C, with 247 mm of rain across 15.8 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 30°C in the first days to 26°C by the end. The sky is clear or mostly clear about 29% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Iwata's 9th-clearest and 10th-windiest month. For the whole year in context, see Iwata's year-round climate.

Daytime high
28°
3rd warmest
Overnight low
22°
10th coldest
Rainfall
247 mm
15.8 wet days
Daylight
12 h 12 min
5:37 AM – 5:49 PM
Cloud cover
62%
9th clearest
Wind
10 km/h
10th windiest
Solar energy
4.09 kWh/m²
Travel score
5.1
out of 10

Iwata is city in Shizuoka prefecture, Japan.

Founded
2005

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 30°C in the first days to 26°C by the end.

A typical September day in Iwata reaches about 28°C in the afternoon and slips back to 22°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 31°C. Set against its neighbours, September runs about 3°C cooler than August and about 5°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13024
23024
33024
43023
53023
62923
72923
82923
92923
102923
112922
122922
132822
142822
152822
162822
172821
182721
192721
202721
212721
222721
232720
242620
252620
262620
272620
282619
292619
302519

How September really feels in Iwata

Once humidity and wind are folded in, September averages 5 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
5
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Iwata weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan10° / 705.90.19.92.7
Feb11° / 896.90.510.73.1
Mar14° / 14810.80.111.74.3
Apr19° / 10°16511.1012.85.9
May23° / 15°18412013.86.4
Jun26° / 20°25815.7014.35.4
Jul30° / 24°27316.9014.14.2
Aug31° / 25°15716.2013.33.8
Sep28° / 22°24715.8012.25.1
Oct23° / 16°21612.5011.16.4
Nov18° / 10°1229.2010.25.9
Dec13° / 716.609.73.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14555
24555
34654
44555
54555
64456
74357
84357
94456
104456
114357
124357
134357
144357
154357
164357
174357
184258
194258
204357
214258
224159
234159
244357
254357
264357
274258
284258
294357
304357

Chance of precipitation in September

Any precipitation

Iwata gets around 247 mm of rain over 15.8 wet days in September. 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 55% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
152
252
353
453
554
654
754
854
955
1055
1155
1254
1354
1454
1553
1653
1753
1853
1953
2053
2152
2252
2352
2451
2551
2651
2751
2851
2950
3050

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 32% of days. Sticky, muggy-or-worse air turns up on roughly 68% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1017265511
2027275311
3027285310
4028285210
5028295110
603930499
7031030489
8131131478
9141231458
10141332447
11151432427
12151532406
13161633385
14171833365
15171934344
16282034324
17292235293
182102335273
193112435252
203122536222
214132635202
224132835181
235142935161
245153035141
256163134131
267173233110
27717343390
28818343180
29919343070
301020352960

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 10 km/h on the calmest days to 11 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2911calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over September. Sunrise moves from 5:25 AM to 5:47 AM, and sunset from 6:11 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:256:11
212.75:266:10
312.75:276:08
412.75:286:07
512.65:286:06
612.65:296:04
712.55:306:03
812.55:316:01
912.55:316:00
1012.45:325:58
1112.45:335:57
1212.45:345:55
1312.35:345:54
1412.35:355:52
1512.35:365:51
1612.25:375:49
1712.25:375:48
1812.15:385:46
1912.15:395:45
2012.15:395:43
2112.05:405:42
2212.05:415:40
2312.05:425:39
2411.95:425:37
2511.95:435:36
2611.85:445:35
2711.85:455:33
2811.85:465:32
2911.75:465:30
3011.75:475:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.09 kWh/m².

For context, solar energy here swings from a low near 2.63 kWh/m² to a high of 5.38 kWh/m² in May across the year — September's 4.09 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.6Bright
34.6Bright
44.5Bright
54.5Bright
64.5Bright
74.4Bright
84.4Bright
94.3Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.1Bright
154.1Bright
164.1Bright
174.0Bright
184.0Moderate
194.0Moderate
203.9Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.8Moderate
263.7Moderate
273.7Moderate
283.7Moderate
293.6Moderate
303.6Moderate
Planning a trip in September

Hazard calendar for Iwata

In seasonPeak

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

Iwata 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 September a good time to visit Iwata?

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

5.1
Sightseeing
6th-best month of the year
5.7
Beach & pool
1st-best month of the year

September is a reasonable time to visit Iwata for sightseeing.

What to pack for Iwata in September

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

In September, Iwata sees daytime highs around 28°C and nights near 22°C. Pack light clothes and rain gear. About 16 days see rain.

light clothesrain gear

Sea temperature near Iwata in September

The nearest coast averages about 26°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 27°C and coldest in February near 16°C.

It's comfortable for a long swim from May 25 to Nov 29 — about 6.2 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb16Cool
Mar16Cool
Apr17Cool
May19Cool
Jun22Refreshing
Jul25Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov21Refreshing
Dec19Cool

UV index in Iwata in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September 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 Iwata peaks around July 20 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 highVery highModerateJul 20UV 10Dec 22UV 3
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May9Very high
Jun10Very high
Jul10Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Iwata in September

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Iwata is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.3× the cleanest month (December, 9 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1721 µg/m³Dec 159 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May19Moderate
Jun16Moderate
Jul12Good
Aug11Good
Sep10Good
Oct11Good
Nov10Good
Dec9Good
Location & terrain

Where is Iwata?

Iwata sits at 34.7°N, 137.8°E, 5 m above sea level, in Japan. The nearest listed city is Fukuroi, 8.0 km away.

Topography around Iwata

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

Within 3 km, the terrain around Iwata has only modest variations in elevation — a maximum elevation change of 36 m around an average of 6 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 262 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,576 m.

The land around Iwata is covered by artificial surfaces (53%) and cropland (37%) within 3 km, water (35%) and artificial surfaces (31%) within 16 km, and trees (45%) and water (44%) within 80 km.

3 km
36 m
16 km
262 m
80 km
2,576 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Fukuroi 8.0 km · Hamamatsu 11 km · Hamakita 13 km · Mori 17 km · Kakegawa 17 km · Kikugawa 25 km · Arai 26 km · Maruobara 27 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 Iwata (34.7°, 137.85°, elevation 5 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).