Japan · 1991–2020

Best time to visit
Muroran.

September leads for comfortable weather in Muroran: typically 21.7°C by day, 15.5°C at night, with 161 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high21.7°C

Typical low15.5°C

Rain in September161 mm

Comfort

September

September · August · July

66climate match

Beach

August

August · September · July

43climate match

Outdoors

June

June · October · May

71climate match

The weakest month is January, scoring 5 against September’s 66 — days reach only 0.7°C, 23° below the 24°C the score treats as ideal.

Month by month

The whole year,
without the guesswork.

The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.

Jan

50.7° / -4.5°

Feb

51.1° / -4.5°

Mar

54.8° / -1.6°

Apr

2310.3° / 2.7°

May

3815.5° / 7.3°

Jun

5918.4° / 11.8°

Jul

6222° / 16.2°

Aug

6524° / 18.5°

Sep

6621.7° / 15.5°

Oct

4516.1° / 9.2°

Nov

109.6° / 3.1°

Dec

53° / -2.3°

Monthly climate evidence for Muroran — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 11 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	0.7°C	-4.5°C	62 mm	15.2	6.4°C	9 h 24	5	Good coverage
February	1.1°C	-4.5°C	57 mm	13.9	4.1°C	10 h 30	5	Strong coverage
March	4.8°C	-1.6°C	60 mm	11.8	4.1°C	11 h 48	5	Good coverage
April	10.3°C	2.7°C	69 mm	8.7	5.7°C	13 h 18	23	Good coverage
May	15.5°C	7.3°C	125 mm	11.4	8.7°C	14 h 34	38	Good coverage
June	18.4°C	11.8°C	113 mm	9.9	13.6°C	15 h 15	59	Good coverage
July	22°C	16.2°C	183 mm	13	17.8°C	14 h 59	62	Good coverage
August	24°C	18.5°C	179 mm	12	20.7°C	13 h 53	65	Good coverage
September	21.7°C	15.5°C	161 mm	11.8	20.0°C	12 h 26	66	Good coverage
October	16.1°C	9.2°C	111 mm	11.1	16.5°C	10 h 59	45	Good coverage
November	9.6°C	3.1°C	99 mm	15.8	12.4°C	9 h 43	10	Good coverage
December	3°C	-2.3°C	74 mm	15.6	9.3°C	9 h 06	5	Good coverage

What has changed

Muroran runs +1.6°C
on the 1961–1990 baseline.

Each bar compares the 2011–2025 daytime average for that month against the same month in 1961–1990, measured at the same station. Months where the older record is too thin to compare are left blank.

Jan

+0.9

Feb

+1.6

Mar

+2.8

Apr

+2.6

May

+2.4

Jun

+1.8

Jul

+2.4

Aug

+1.1

Sep

+1.7

Oct

+1.0

Nov

+1.5

Dec

-0.1

September daytime highs, 2011–2022. Last recorded: 22.6°C.

Records at MURORAN, 1951–2025
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	9.5°C13 Jan 2023	-13.4°C12 Jan 1961	86 mm31 Jan 1970	167 mm1970 · driest 11 mm in 2023	74
February	13.8°C19 Feb 2024	-12.1°C3 Feb 2001	65 mm27 Feb 1972	187 mm1958 · driest 9 mm in 1989	74
March	16.7°C28 Mar 2018	-9.6°C4 Mar 1986	86 mm21 Mar 1975	143 mm1975 · driest 4 mm in 2011	74
April	23.1°C26 Apr 2014	-4.8°C1 Apr 1978	79 mm16 Apr 1966	201 mm1964 · driest 6 mm in 2014	74
May	27.6°C26 May 2019	0.4°C4 May 1971	97 mm2 May 1998	334 mm1955 · driest 5 mm in 2003	73
June	28.7°C26 Jun 2010	5.0°C2 Jun 1969	95 mm13 Jun 1983	325 mm1983 · driest 6 mm in 1973	73
July	31.2°C20 Jul 2021	8.5°C3 Jul 1989	135 mm23 Jul 2008	351 mm2009 · driest 23 mm in 1997	74
August	32.2°C11 Aug 1951	11.5°C18 Aug 1971	166 mm12 Aug 2010	574 mm1981 · driest 23 mm in 1991	73
September	31.0°C9 Sep 2019	5.9°C30 Sep 1969	119 mm7 Sep 1962	356 mm2000 · driest 10 mm in 1995	72
October	24.6°C4 Oct 2021	-1.0°C25 Oct 1964	99 mm5 Oct 1961	249 mm1961 · driest 31 mm in 1965	73
November	21.4°C3 Nov 2023	-7.2°C29 Nov 1971	170 mm7 Nov 1975	283 mm1975 · driest 22 mm in 2024	72
December	14.4°C4 Dec 1989	-12.0°C24 Dec 1984	58 mm23 Dec 2016	136 mm2004 · driest 10 mm in 2020	73

Typical days per month at MURORAN, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	16	1
February	0	0	15	<1
March	0	0	13	1
April	0	0	2	2
May	<1	0	0	3
June	<1	0	0	3
July	6	<1	0	4
August	10	<1	0	5
September	3	0	0	4
October	0	0	0	3
November	0	0	3	2
December	0	0	13	1

How often, not how much — every day in MURORAN’s record sorted by what it was actually like, rather than averaged
Month	Warm & dry days	Wet days	Washouts	Week with 3+ wet days	Daytime mean has ranged
January	0%	42%	4%	54%	-1.1–1.9°C
February	0%	37%	4%	44%	-1.4–2.2°C
March	0%	33%	6%	35%	2.3–6.5°C
April	<1%	31%	9%	34%	8.0–11.5°C
May	8%	33%	11%	34%	12.9–16.8°C
June	22%	34%	13%	40%	15.8–20.0°C
July	45%	36%	15%	46%	19.5–23.7°C
August	59%	40%	17%	50%	22.0–25.5°C
September	48%	37%	16%	44%	19.8–22.7°C
October	5%	36%	11%	43%	14.4–16.9°C
November	<1%	43%	8%	57%	7.3–11.0°C
December	0%	43%	4%	55%	0.9–4.9°C

A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.

1951Each stripe is one year’s mean temperature against the 47-year average. Warmest: 2015. Coolest: 1984.2018

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 2129101
NOAA station: JA000047423 · MURORAN
Station distance: 0.4 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 16 usable years
Daylight: Calculated from latitude 42.32°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 11 km from the place centre. A sheltered bay can run warmer than the open sea it is measured from.
Important limit: Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.

These places read the same station, so their numbers are identical — distance from MURORAN is what differs

Noboribetsu→Date→Tōyako-onsemmachi→Toyoura→Sōbetsu→Washibetsu→

Or put two places side by side: Muroran vs Noboribetsu

Best time to visitMuroran.