Tainai weather in September

In September, Tainai sees average daytime highs of 25°C and overnight lows near 17°C, with 167 mm of rain across 15 wet days and about 12.3 hours of daylight. It is the 3rd-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 22°C by the end. The sky is clear or mostly clear about 21% of the time in September, and the air most often feels humid.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Tainai's 5th-clearest and 9th-windiest month. For the whole year in context, see Tainai's year-round climate.

Daytime high
25°
3rd warmest
Overnight low
17°
10th coldest
Rainfall
167 mm
15 wet days
Daylight
12 h 12 min
5:29 AM – 5:44 PM
Cloud cover
68%
5th clearest
Wind
7 km/h
9th windiest
Solar energy
3.83 kWh/m²
Travel score
5.7
out of 10

Tainai is city in Niigata Prefecture, Japan.

Density
108/km²
people per km²
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 27°C in the first days to 22°C by the end.

A typical September day in Tainai reaches about 25°C in the afternoon and slips back to 17°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 29°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12720
22720
32720
42720
52719
62619
72619
82619
92619
102618
112618
122518
132518
142518
152517
162417
172417
182417
192416
202416
212316
222316
232315
242315
252315
262215
272215
282214
292214
302214

How September really feels in Tainai

Once humidity and wind are folded in, September 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

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

Tainai weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -2°22126.324.29.70.0
Feb / -2°15822.119.910.50.0
Mar / -0°16521.113.411.70.8
Apr14° / 13416.12.6133.5
May20° / 11°14314.40145.6
Jun24° / 16°18614.8014.65.8
Jul27° / 20°31519.5014.44.8
Aug29° / 21°21517.2013.54.8
Sep25° / 17°16715012.35.7
Oct18° / 11°168160115.0
Nov12° / 18119.339.92.4
Dec / -0°22725.316.89.40.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 63%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14357
24258
34159
44159
54159
64159
74159
84060
94060
103961
113961
123862
133862
143763
153763
163664
173763
183565
193565
203565
213565
223466
233466
243466
253565
263466
273565
283565
293664
303664

Chance of precipitation in September

Any precipitation

Tainai gets around 167 mm of rain over 15 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 51% and peaks near 55% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
155
255
354
454
554
654
754
853
953
1053
1153
1252
1352
1451
1550
1650
1749
1849
1949
2048
2148
2248
2348
2449
2549
2650
2750
2851
2951
3052

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the humid band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 37% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1062442271
2062543251
3062643231
4172743221
5182842200
6192942190
71103041170
82113041160
92133140150
103143139130
114153137120
125173136110
136183134100
14720313390
15921313180
161122322970
171224322660
181425312450
191626312250
201827312040
212028301830
222229301630
232430291420
242631281320
252832271120
26303326910
27323425810
28343524710
29363522610
30383621500

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 7 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
17calm
27calm
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

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 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 72 minutes over September. Sunrise moves from 5:16 AM to 5:42 AM, and sunset from 6:08 PM to 5:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:166:08
212.85:176:06
312.85:186:05
412.75:196:03
512.75:206:02
612.75:216:00
712.65:215:59
812.65:225:57
912.55:235:55
1012.55:245:54
1112.55:255:52
1212.45:265:50
1312.45:275:49
1412.35:285:47
1512.35:295:46
1612.25:295:44
1712.25:305:42
1812.25:315:41
1912.15:325:39
2012.15:335:37
2112.05:345:36
2212.05:355:34
2311.95:365:33
2411.95:375:31
2511.95:385:29
2611.85:385:28
2711.85:395:26
2811.75:405:24
2911.75:415:23
3011.75:425:21

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.83 kWh/m².

For context, solar energy here swings from a low near 1.68 kWh/m² to a high of 5.51 kWh/m² in May across the year — September's 3.83 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.2Bright
44.2Bright
54.2Bright
64.1Bright
74.1Bright
84.0Bright
94.0Bright
104.0Moderate
113.9Moderate
123.9Moderate
133.9Moderate
143.8Moderate
153.8Moderate
163.8Moderate
173.7Moderate
183.7Moderate
193.7Moderate
203.6Moderate
213.6Moderate
223.6Moderate
233.6Moderate
243.5Moderate
253.5Moderate
263.5Moderate
273.5Moderate
283.4Moderate
293.4Moderate
303.4Moderate
Planning a trip in September

Hazard calendar for Tainai

In seasonPeak

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

Tainai 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 Tainai?

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

5.7
Sightseeing
2nd-best month of the year
4.9
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Tainai for sightseeing.

What to pack for Tainai in September

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

In September, Tainai sees daytime highs around 25°C and nights near 17°C. Pack rain gear. Worth having: light clothes. About 15 days see rain.

rain gearlight clothes

Sea temperature near Tainai in September

The nearest coast averages about 25°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 26°C and coldest in March near 9°C.

It's comfortable for a long swim from Jun 21 to Oct 29 — about 4.3 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan12Bracing
Feb10Bracing
Mar9Bracing
Apr11Bracing
May15Bracing
Jun20Cool
Jul23Refreshing
Aug26Warm
Sep25Warm
Oct22Refreshing
Nov18Cool
Dec15Bracing

UV index in Tainai in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Tainai 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 (moderate).

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
Jan2Moderate
Feb3Moderate
Mar4Moderate
Apr6High
May8Very high
Jun8Very high
Jul9Very high
Aug10Very high
Sep8Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Tainai 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 Tainai 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 1421 µg/m³Dec 159 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar20Moderate
Apr21Moderate
May19Moderate
Jun15Moderate
Jul14Moderate
Aug12Good
Sep10Good
Oct10Good
Nov10Good
Dec9Good
Location & terrain

Where is Tainai?

Tainai sits at 38.1°N, 139.4°E, 48 m above sea level, in Japan. The nearest listed city is Shibata, 14 km away.

Topography around Tainai

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

Within 3 km, the terrain around Tainai has significant variations in elevation — a maximum elevation change of 325 m around an average of 33 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 938 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,110 m.

The land around Tainai is covered by cropland (46%), trees (26%) and artificial surfaces (24%) within 3 km, trees (41%), water (28%) and cropland (20%) within 16 km, and trees (52%) and water (35%) within 80 km.

3 km
325 m
16 km
938 m
80 km
2,110 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Shibata 14 km · Murakami 20 km · Suibara 29 km · Agano 30 km · Kameda-honchō 34 km · Niigata 36 km · Niitsu-honchō 38 km · Gosen 42 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 Tainai (38.0646°, 139.4056°, elevation 48 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).