Japan · 1991–2020

Best time to visit
Ryōtsu-minato.

June leads for comfortable weather in Ryōtsu-minato: typically 23.2°C by day, 16.1°C at night, with 136 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJune

Typical high23.2°C

Typical low16.1°C

Rain in June136 mm

Comfort

June

June · May · September

75climate match

Beach

August

August · September · June

66climate match

Outdoors

May

May · October · April

80climate match

The weakest month is January, scoring 5 against June’s 75 — days reach only 6.4°C, 18° 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

56.4° / 0.8°

Feb

57° / 0.5°

Mar

59.6° / 2.4°

Apr

3714.9° / 6.5°

May

6619.9° / 11.4°

Jun

7523.2° / 16.1°

Jul

3527.1° / 21°

Aug

4629.3° / 22.4°

Sep

6025.8° / 18.5°

Oct

5720.4° / 13.4°

Nov

2115° / 7.9°

Dec

59.9° / 3.4°

Monthly climate evidence for Ryōtsu-minato — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 8 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	6.4°C	0.8°C	149 mm	22.2	12.2°C	9 h 47	5	Strong coverage
February	7°C	0.5°C	104 mm	17.7	10.4°C	10 h 43	5	Good coverage
March	9.6°C	2.4°C	117 mm	17.2	9.8°C	11 h 50	5	Good coverage
April	14.9°C	6.5°C	104 mm	12	10.8°C	13 h 08	37	Good coverage
May	19.9°C	11.4°C	92 mm	9.7	14.2°C	14 h 12	66	Good coverage
June	23.2°C	16.1°C	136 mm	9.8	19.0°C	14 h 48	75	Good coverage
July	27.1°C	21°C	286 mm	13.2	22.8°C	14 h 34	35	Good coverage
August	29.3°C	22.4°C	158 mm	9.8	26.1°C	13 h 38	46	Good coverage
September	25.8°C	18.5°C	176 mm	12	24.9°C	12 h 23	60	Good coverage
October	20.4°C	13.4°C	165 mm	13.8	21.5°C	11 h 08	57	Good coverage
November	15°C	7.9°C	192 mm	18.7	18.0°C	10 h 03	21	Good coverage
December	9.9°C	3.4°C	200 mm	23.3	15.0°C	9 h 32	5	Strong coverage

What has changed

Ryōtsu-minato runs +1.2°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

+0.7

Feb

+1.4

Mar

+1.9

Apr

+0.7

May

+1.7

Jun

+1.4

Jul

+1.7

Aug

+0.9

Sep

+1.4

Oct

+1.1

Nov

—

Dec

+0.6

June daytime highs, 2011–2025. Last recorded: 24.6°C.

Records at AIKAWA, 1951–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	16.3°C4 Jan 1982	-6.2°C25 Jan 2023	55 mm27 Jan 2002	271 mm1963 · driest 50 mm in 2006	75
February	20.7°C22 Feb 2004	-5.8°C6 Feb 1984	43 mm22 Feb 1975	166 mm1976 · driest 29 mm in 2003	75
March	23.4°C27 Mar 2025	-6.4°C7 Mar 1971	57 mm30 Mar 1972	191 mm1972 · driest 32 mm in 2003	75
April	28.0°C13 Apr 1998	-1.8°C2 Apr 1984	58 mm20 Apr 1952	176 mm1964 · driest 0 mm in 2025	75
May	30.0°C16 May 2016	2.6°C5 May 1966	72 mm16 May 1983	233 mm1963 · driest 0 mm in 2025	74
June	32.1°C13 Jun 2013	8.0°C3 Jun 1970	185 mm26 Jun 1978	422 mm1978 · driest 0 mm in 2025	74
July	37.4°C29 Jul 2018	12.1°C1 Jul 1967	240 mm15 Jul 2002	448 mm2006 · driest 0 mm in 2025	75
August	38.5°C9 Aug 2023	14.6°C20 Aug 1956	134 mm4 Aug 1961	330 mm1995 · driest 0 mm in 2025	74
September	37.4°C3 Sep 2020	10.3°C27 Sep 1969	131 mm11 Sep 2012	349 mm2010 · driest 0 mm in 2025	74
October	31.5°C6 Oct 2018	4.4°C31 Oct 1983	102 mm23 Oct 2017	210 mm2009 · driest 0 mm in 2025	74
November	24.9°C1 Nov 1977	-2.8°C30 Nov 1970	88 mm11 Nov 2021	287 mm1951 · driest 0 mm in 2025	74
December	20.0°C4 Dec 2018	-4.6°C28 Dec 1969	103 mm16 Dec 1993	373 mm2014 · driest 0 mm in 2025	74

Typical days per month at AIKAWA, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	6	4
February	0	0	7	2
March	0	0	3	3
April	<1	0	0	3
May	3	0	0	3
June	7	<1	0	3
July	20	6	0	5
August	27	11	0	3
September	16	3	0	4
October	1	0	0	4
November	0	0	0	5
December	0	0	1	6

How often, not how much — every day in AIKAWA’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%	69%	15%	91%	4.3–7.7°C
February	<1%	61%	10%	85%	4.1–8.1°C
March	<1%	51%	10%	72%	7.3–10.5°C
April	7%	40%	14%	53%	13.3–16.4°C
May	30%	34%	13%	37%	17.9–21.3°C
June	57%	35%	14%	47%	21.5–24.4°C
July	63%	38%	18%	44%	24.7–28.7°C
August	71%	30%	14%	36%	27.2–30.5°C
September	60%	41%	19%	54%	23.9–27.2°C
October	30%	43%	17%	60%	18.6–21.2°C
November	3%	59%	22%	84%	13.3–16.2°C
December	0%	72%	22%	95%	7.4–10.8°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 41-year average. Warmest: 2025. Coolest: 1976.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 1853371
NOAA station: JA000047602 · AIKAWA
Station distance: 18.8 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 16 usable years
Daylight: Calculated from latitude 38.08°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 8 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 AIKAWA is what differs

Sado→Yoshii→Yokkamachi→Yahata→Washizaki→Waki→

Or put two places side by side: Ryōtsu-minato vs Sado

Best time to visitRyōtsu-minato.

June

August

May

The whole year,without the guesswork.

Ryōtsu-minato runs +1.2°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Ryōtsu-minato.

The whole year,
without the guesswork.

Ryōtsu-minato runs +1.2°C
on the 1961–1990 baseline.

Nearby, measured,
and named.