Muroran weather in September

In September, Muroran sees average daytime highs of 20°C and overnight lows near 17°C, with 166 mm of rain across 13 wet days and about 12.3 hours of daylight. It is the 2nd-warmest and 2nd-wettest month of the year here.

Highs ease over the month, from about 21°C in the first days to 18°C by the end. The sky is clear or mostly clear about 30% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Muroran's 6th-clearest and 7th-windiest month. For the whole year in context, see Muroran's year-round climate.

Daytime high
20°
2nd warmest
Overnight low
17°
11th coldest
Rainfall
166 mm
13 wet days
Daylight
12 h 18 min
5:22 AM – 5:39 PM
Cloud cover
63%
6th clearest
Wind
16 km/h
7th windiest
Solar energy
3.79 kWh/m²
Travel score
5.8
out of 10

Muroran is city in Hokkaido, Japan.

Density
1,187/km²
people per km²
Founded
1922

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 21°C in the first days to 18°C by the end.

A typical September day in Muroran reaches about 20°C in the afternoon and slips back to 17°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 18°C and 22°C. Set against its neighbours, September runs about 2°C cooler than August and about 6°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
12219
22219
32219
42119
52119
62119
72119
82118
92118
102118
112118
122118
132118
142018
152017
162017
172017
182017
192017
202017
211917
221916
231916
241916
251916
261916
271815
281815
291815
301815

How September really feels in Muroran

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.

Muroran weather by month

How September compares with the rest of the year at a glance. September 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-1° / -4°508.510.19.30.0
Feb-0° / -4°437.4710.30.0
Mar / -1°579.1611.60.0
Apr / 769.11.513.10.5
May11° / 11211.1014.42.5
Jun15° / 12°10410.30154.5
Jul20° / 17°15313014.85.6
Aug22° / 19°18112.6013.76.0
Sep20° / 17°16613012.35.8
Oct14° / 11°10310.90.110.84.2
Nov / 80111.79.61.0
Dec / -1°69119.790.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 58%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13763
23763
33763
43763
53763
63862
73862
83961
93961
103961
114060
124159
134258
144258
154357
164357
174456
184555
194654
204654
214654
224654
234654
244654
254654
264654
274654
284654
294753
304753

Chance of precipitation in September

Any precipitation

Muroran gets around 166 mm of rain over 13 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 43% and peaks near 46% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
145
245
345
446
546
646
746
846
946
1046
1146
1245
1345
1444
1544
1643
1743
1843
1942
2042
2142
2241
2341
2441
2541
2640
2740
2840
2940
3039

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 17% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
141835349
241936329
352036318
462136308
572236287
682336267
792436256
8112536236
9122635225
10142735205
11162834194
12182833174
13202932163
14223030143
15253129133
16273128122
17293226102
1831332592
1934332481
2036342271
2138352161
2240351951
2341361841
2443361631
2545371530
2647371420
2749371320
2851361210
2953351110
3055341010

Wind in September

Winds average 16 km/h in September.

Across September, daily wind ranges from about 15 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2317light breeze
2417light breeze
2517light breeze
2617light breeze
2717light breeze
2817light breeze
2917light breeze
3017light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:06 AM to 5:37 AM, and sunset from 6:06 PM to 5:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:066:06
213.05:076:04
312.95:086:02
412.95:096:01
512.85:105:59
612.85:115:57
712.75:125:55
812.75:135:53
912.65:145:52
1012.65:155:50
1112.55:165:48
1212.55:185:46
1312.45:195:44
1412.45:205:42
1512.35:215:41
1612.35:225:39
1712.25:235:37
1812.25:245:35
1912.15:255:33
2012.15:265:31
2112.05:275:30
2212.05:295:28
2311.95:305:26
2411.95:315:24
2511.85:325:22
2611.85:335:20
2711.75:345:19
2811.75:355:17
2911.65:365:15
3011.65:375:13

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.79 kWh/m².

For context, solar energy here swings from a low near 1.73 kWh/m² to a high of 5.42 kWh/m² in May across the year — September's 3.79 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.0Bright
24.0Bright
34.0Moderate
44.0Moderate
53.9Moderate
63.9Moderate
73.9Moderate
83.9Moderate
93.9Moderate
103.9Moderate
113.8Moderate
123.8Moderate
133.8Moderate
143.8Moderate
153.8Moderate
163.8Moderate
173.8Moderate
183.8Moderate
193.7Moderate
203.7Moderate
213.7Moderate
223.7Moderate
233.7Moderate
243.6Moderate
253.6Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Muroran

In seasonPeak

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

Muroran sits in the Pacific typhoon belt; the season peaks July–October.

Muroran's rainy season runs May–October, when most of the year's rain falls.

Pacific typhoon
Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Muroran?

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

5.8
Sightseeing
2nd-best month of the year
3.0
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Muroran for sightseeing.

What to pack for Muroran in September

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

In September, Muroran sees daytime highs around 20°C and nights near 17°C. Worth packing: rain gear. About 13 days see rain.

rain gear

Sea temperature near Muroran in September

The nearest coast averages about 20°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 21°C and coldest in February near 4°C.

It's comfortable for a long swim from Aug 9 to Sep 13 — about 1.2 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°C)Comfort
Jan6Bracing
Feb4Bracing
Mar4Bracing
Apr6Bracing
May9Bracing
Jun14Bracing
Jul18Cool
Aug21Refreshing
Sep20Refreshing
Oct17Cool
Nov12Bracing
Dec9Bracing

UV index in Muroran in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Muroran peaks around August 18 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighVery highHighModerateLowAug 18UV 8Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar3Moderate
Apr5High
May8Very high
Jun7High
Jul5Moderate
Aug9Very high
Sep6High
Oct4Moderate
Nov2Low
Dec1Low

Air quality in Muroran 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 Muroran is worst in April — around 17 µg/m³ PM2.5 (moderate), about 2.6× the cleanest month (December, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1216 µg/m³Dec 177 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb11Good
Mar16Moderate
Apr17Moderate
May14Moderate
Jun9Good
Jul8Good
Aug8Good
Sep8Good
Oct9Good
Nov8Good
Dec6Good
Location & terrain

Where is Muroran?

Muroran sits at 42.3°N, 141.0°E, 8 m above sea level, in Japan. The nearest listed city is Date, 19 km away.

Topography around Muroran

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

Within 3 km, the terrain around Muroran has only modest variations in elevation — a maximum elevation change of 185 m around an average of 21 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 901 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,867 m.

The land around Muroran is covered by water (49%), trees (25%) and artificial surfaces (23%) within 3 km, water (76%) within 16 km, and trees (48%) and water (45%) within 80 km.

3 km
185 m
16 km
901 m
80 km
1,867 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Date 19 km · Noboribetsu 22 km · Shiraoi 39 km · Honchō 53 km · Yakumo 60 km · Niseko 60 km · Tomakomai 62 km · Kamiiso 62 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 Muroran (42.3172°, 140.9881°, elevation 8 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).