Ryūō weather in September

In September, Ryūō sees average daytime highs of 22°C and overnight lows near 15°C, with 185 mm of rain across 14.6 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 24°C in the first days to 20°C by the end. The sky is clear or mostly clear about 20% of the time in September, and the air most often feels dry.

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 Ryūō's 10th-clearest and 9th-windiest month. For the whole year in context, see Ryūō's year-round climate.

Daytime high
22°
3rd warmest
Overnight low
15°
10th coldest
Rainfall
185 mm
14.6 wet days
Daylight
12 h 12 min
5:34 AM – 5:47 PM
Cloud cover
69%
10th clearest
Wind
5 km/h
9th windiest
Solar energy
3.88 kWh/m²
Travel score
5.7
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 24°C in the first days to 20°C by the end.

A typical September day in Ryūō reaches about 22°C in the afternoon and slips back to 15°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 18°C and 26°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°151015202530
Avg high (°C)Avg low (°C)
12517
22417
32417
42417
52416
62416
72416
82416
92316
102316
112316
122315
132315
142315
152215
162215
172214
182214
192214
202114
212114
222113
232113
242113
252013
262012
272012
282012
292012
301912

How September really feels in Ryūō

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.

Ryūō 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
Jan / -7°646.879.90.0
Feb / -6°727.96.510.70.0
Mar / -3°12512.87.611.70.9
Apr13° / 12112.62.112.93.5
May18° / 13012.80.113.95.4
Jun21° / 13°17716.3014.45.2
Jul25° / 17°19917.4014.25.4
Aug26° / 18°13916.8013.35.6
Sep22° / 15°18514.6012.25.7
Oct17° / 18613011.14.9
Nov11° / 859.20.510.12.8
Dec / -3°607.44.29.60.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% 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 64%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13763
23763
33763
43763
53862
63763
73763
83664
93664
103664
113763
123664
133664
143763
153664
163664
173664
183664
193664
203664
213565
223565
233565
243565
253664
263664
273664
283664
293664
303664

Chance of precipitation in September

Any precipitation

Ryūō gets around 185 mm of rain over 14.6 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 49% and peaks near 52% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
152
252
352
452
551
651
750
850
949
1049
1149
1248
1348
1447
1547
1647
1747
1847
1947
2048
2148
2248
2349
2449
2549
2650
2750
2851
2951
3051

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 35% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
17275610
2728569
3829549
4930538
51130518
61231507
71431487
81532466
91732456
101933435
112133415
122433394
132634374
142934353
153133333
163433302
173733282
184032262
194332241
204631221
214831201
225130181
235330161
245629141
255929120
266128110
27632890
28652780
29672670
30692560

Wind in September

Winds average 5 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

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 5:22 AM to 5:45 AM, and sunset from 6:09 PM to 5:26 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:226:09
212.85:236:08
312.75:246:07
412.75:246:05
512.65:256:04
612.65:266:02
712.65:276:01
812.55:275:59
912.55:285:58
1012.55:295:56
1112.45:305:55
1212.45:315:53
1312.35:315:52
1412.35:325:50
1512.35:335:48
1612.25:345:47
1712.25:345:45
1812.15:355:44
1912.15:365:42
2012.15:375:41
2112.05:385:39
2212.05:385:38
2312.05:395:36
2411.95:405:35
2511.95:415:33
2611.85:425:32
2711.85:425:30
2811.85:435:29
2911.75:445:27
3011.75:455:26

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.88 kWh/m².

For context, solar energy here swings from a low near 2.63 kWh/m² to a high of 5.51 kWh/m² in May across the year — September's 3.88 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.3Bright
34.3Bright
44.3Bright
54.2Bright
64.2Bright
74.1Bright
84.1Bright
94.1Bright
104.0Bright
114.0Bright
124.0Moderate
133.9Moderate
143.9Moderate
153.9Moderate
163.8Moderate
173.8Moderate
183.8Moderate
193.8Moderate
203.7Moderate
213.7Moderate
223.7Moderate
233.6Moderate
243.6Moderate
253.6Moderate
263.5Moderate
273.5Moderate
283.5Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Ryūō?

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

5.7
Sightseeing
1st-best month of the year
4.0
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Ryūō for sightseeing.

What to pack for Ryūō in September

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

In September, Ryūō sees daytime highs around 22°C and nights near 15°C. Pack rain gear. Worth having: light clothes. About 15 days see rain.

rain gearlight clothes

Sea temperature near Ryūō 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 at the nearest coast (about 59 km away) is warmest in August at about 27°C and coldest in February near 15°C.

It's comfortable for a long swim from May 30 to Nov 23 — about 5.9 months when the water holds above 20°C.

15°20°25°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan16Cool
Feb15Cool
Mar15Cool
Apr17Cool
May19Cool
Jun22Refreshing
Jul24Warm
Aug27Warm
Sep26Warm
Oct23Refreshing
Nov21Refreshing
Dec18Cool

UV index in Ryūō 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 Ryūō peaks around July 14 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 highExtremeVery highModerateJul 14UV 11Dec 21UV 2
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar6High
Apr7Very high
May9Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep9Very high
Oct6High
Nov4Moderate
Dec2Moderate

Air quality in Ryūō 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 Ryūō is worst in April — around 21 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1821 µg/m³Dec 1810 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar19Moderate
Apr21Moderate
May20Moderate
Jun18Moderate
Jul15Moderate
Aug14Moderate
Sep13Moderate
Oct12Moderate
Nov11Good
Dec10Good
Location & terrain

Where is Ryūō?

Ryūō sits at 35.6°N, 138.5°E, 288 m above sea level, in Japan. The nearest listed city is Kai, 4.0 km away.

Topography around Ryūō

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

Within 3 km, the terrain around Ryūō has only modest variations in elevation — a maximum elevation change of 93 m around an average of 297 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,312 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,735 m.

The land around Ryūō is covered by artificial surfaces (55%) and cropland (23%) within 3 km, trees (62%) and artificial surfaces (21%) within 16 km, and trees (83%) within 80 km.

3 km
93 m
16 km
2,312 m
80 km
3,735 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Kai 4.0 km · Shōwa 4.0 km · Minami-Alps 5.0 km · Minamiarupusu 6.0 km · Chūō 6.0 km · Kofu 6.0 km · Nirasaki 7.0 km · Isawa 12 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 Ryūō (35.65°, 138.5°, elevation 288 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. 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).