United States · 1991–2020

Best time to visit
South Yarmouth.

June leads for comfortable weather in South Yarmouth: typically 22.7°C by day, 14.1°C at night, with 86 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortJune

Typical high22.7°C

Typical low14.1°C

Rain in June86 mm

Comfort

June

June · September · July

83climate match

Beach

July

July · August · June

75climate match

Outdoors

May

May · September · June

74climate match

The weakest month is January, scoring 5 against June’s 83 — days reach only 3.7°C, 20° 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

53.7° / -4.8°

Feb

54.6° / -4.2°

Mar

57.3° / -1.2°

Apr

2512.4° / 3.3°

May

5517.8° / 8.8°

Jun

8322.7° / 14.1°

Jul

7926.5° / 18°

Aug

7926° / 17.4°

Sep

8022.4° / 13.1°

Oct

4716.8° / 7.5°

Nov

2311.7° / 2.7°

Dec

56.8° / -1.7°

Monthly climate evidence for South Yarmouth — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 7 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	3.7°C	-4.8°C	90 mm	9.2	4.7°C	9 h 28	5	Good coverage
February	4.6°C	-4.2°C	82 mm	8.4	3.3°C	10 h 32	5	Good coverage
March	7.3°C	-1.2°C	105 mm	8.9	3.6°C	11 h 48	5	Good coverage
April	12.4°C	3.3°C	101 mm	9.9	6.2°C	13 h 16	25	Good coverage
May	17.8°C	8.8°C	90 mm	9.1	10.0°C	14 h 30	55	Good coverage
June	22.7°C	14.1°C	86 mm	7.4	14.8°C	15 h 11	83	Good coverage
July	26.5°C	18°C	70 mm	6	19.0°C	14 h 55	79	Good coverage
August	26°C	17.4°C	80 mm	7	20.1°C	13 h 51	79	Good coverage
September	22.4°C	13.1°C	95 mm	6.7	18.4°C	12 h 25	80	Good coverage
October	16.8°C	7.5°C	108 mm	8.9	14.7°C	11 h 01	47	Good coverage
November	11.7°C	2.7°C	102 mm	8.7	10.4°C	9 h 46	23	Good coverage
December	6.8°C	-1.7°C	109 mm	10.4	7.2°C	9 h 10	5	Good coverage

Records at HYANNIS BARNSTABLE MUNI AP, 1998–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	17.8°C12 Jan 2020	-21.7°C16 Jan 2004	73 mm20 Jan 2019	194 mm2023 · driest 32 mm in 2022	29
February	17.2°C10 Feb 2023	-22.1°C4 Feb 2023	50 mm4 Feb 2022	164 mm2018 · driest 23 mm in 2007	29
March	22.2°C21 Mar 2012	-18.2°C7 Mar 2015	77 mm30 Mar 2003	199 mm2010 · driest 13 mm in 2006	29
April	30.0°C26 Apr 2009	-6.6°C2 Apr 2015	69 mm13 Apr 2011	190 mm2007 · driest 26 mm in 2012	29
May	31.7°C31 May 2013	-2.8°C7 May 2001	65 mm18 May 2007	166 mm2006 · driest 23 mm in 2015	29
June	33.3°C21 Jun 2012	2.2°C2 Jun 2026	95 mm7 Jun 2006	255 mm2013 · driest 4 mm in 1999	29
July	37.8°C5 Jul 1999	7.8°C21 Jul 2000	79 mm7 Jul 2017	159 mm2026 · driest 9 mm in 2022	29
August	35.0°C2 Aug 2006	7.2°C19 Aug 2025	97 mm8 Aug 2023	185 mm2023 · driest 18 mm in 2016	28
September	32.2°C1 Sep 2010	0.6°C30 Sep 2000	90 mm2 Sep 2021	287 mm2021 · driest 25 mm in 2014	28
October	29.4°C9 Oct 2011	-3.9°C31 Oct 2001	115 mm25 Oct 2017	210 mm2005 · driest 17 mm in 2013	28
November	23.3°C7 Nov 2020	-10.0°C25 Nov 2000	91 mm3 Nov 2007	216 mm2018 · driest 26 mm in 2001	28
December	19.4°C4 Dec 1998	-14.4°C25 Dec 1999	67 mm5 Dec 2020	212 mm2019 · driest 10 mm in 2021	28

Typical days per month at HYANNIS BARNSTABLE MUNI AP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)
January	0	0	25	3
February	0	0	23	3
March	0	0	19	3
April	<1	<1	7	3
May	2	<1	<1	3
June	10	1	0	3
July	23	4	0	2
August	21	3	0	2
September	7	<1	0	3
October	<1	0	2	3
November	0	0	10	3
December	0	0	21	4

How often, not how much — every day in HYANNIS BARNSTABLE MUNI AP’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%	29%	10%	34%	1.8–6.4°C
February	0%	29%	10%	33%	1.2–6.9°C
March	<1%	29%	11%	37%	5.7–9.9°C
April	4%	32%	11%	38%	10.9–13.9°C
May	27%	30%	10%	33%	16.6–19.2°C
June	63%	25%	8%	25%	21.2–24.5°C
July	80%	20%	7%	13%	24.7–28.3°C
August	77%	22%	7%	21%	24.6–27.8°C
September	61%	23%	11%	23%	21.4–23.4°C
October	17%	28%	11%	31%	15.4–18.3°C
November	2%	28%	10%	34%	10.2–13.1°C
December	0%	32%	12%	43%	4.4–8.8°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.

1998Each stripe is one year’s mean temperature against the 28-year average. Warmest: 2020. Coolest: 2003.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4951579
NOAA station: USW00094720 · HYANNIS BARNSTABLE MUNI AP
Station distance: 7.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 22 usable years
Daylight: Calculated from latitude 41.67°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 7 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 HYANNIS BARNSTABLE MUNI AP is what differs

Yarmouth→West Yarmouth→Yarmouth Port→South Dennis→East Dennis→Dennis→

Or put two places side by side: South Yarmouth vs Yarmouth

Best time to visitSouth Yarmouth.

June

July

May

The whole year,without the guesswork.

Nearby, measured,and named.

Best time to visit
South Yarmouth.

The whole year,
without the guesswork.

Nearby, measured,
and named.