United States · 1991–2020

Best time to visit
Sullivan.

August leads for comfortable weather in Sullivan: typically 25.8°C by day, 14.6°C at night, with 83 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortAugust

Typical high25.8°C

Typical low14.6°C

Rain in August83 mm

Comfort

August

August · July · June

83climate match

Beach

July

July · August · June

62climate match

Outdoors

September

September · May · June

75climate match

The weakest month is January, scoring 5 against August’s 83 — days reach only 0.1°C, 24° 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

50.1° / -10.3°

Feb

51.6° / -8.8°

Mar

55.6° / -4.4°

Apr

1711.9° / 1°

May

4718° / 6.5°

Jun

7523.3° / 11.6°

Jul

8226.2° / 14.9°

Aug

8325.8° / 14.6°

Sep

6821.3° / 10.8°

Oct

2914.5° / 5.1°

Nov

58.8° / -0.1°

Dec

53.3° / -6°

Monthly climate evidence for Sullivan — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 17 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	0.1°C	-10.3°C	118 mm	10.1	5.6°C	9 h 10	5	Good coverage
February	1.6°C	-8.8°C	98 mm	7.9	4.0°C	10 h 22	5	Good coverage
March	5.6°C	-4.4°C	136 mm	9.7	3.4°C	11 h 46	5	Good coverage
April	11.9°C	1°C	122 mm	9.4	4.3°C	13 h 24	17	Good coverage
May	18°C	6.5°C	116 mm	10.2	6.4°C	14 h 46	47	Good coverage
June	23.3°C	11.6°C	110 mm	9.4	9.1°C	15 h 32	75	Good coverage
July	26.2°C	14.9°C	82 mm	7.4	11.7°C	15 h 14	82	Good coverage
August	25.8°C	14.6°C	83 mm	7.2	13.0°C	14 h 02	83	Good coverage
September	21.3°C	10.8°C	116 mm	8	12.4°C	12 h 28	68	Good coverage
October	14.5°C	5.1°C	149 mm	9.3	11.3°C	10 h 54	29	Good coverage
November	8.8°C	-0.1°C	151 mm	9.1	9.6°C	9 h 31	5	Good coverage
December	3.3°C	-6°C	145 mm	11.3	7.7°C	8 h 51	5	Good coverage

Records at ACADIA NP, 1982–2014
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	13.9°C9 Jan 2008	-29.4°C20 Jan 1994	133 mm5 Jan 1992	272 mm1998 · driest 19 mm in 2004	32
February	16.1°C21 Feb 1994	-27.8°C7 Feb 1993	82 mm19 Feb 1998	232 mm2008 · driest 6 mm in 2004	32
March	27.8°C22 Mar 2012	-23.9°C7 Mar 1989	101 mm10 Mar 2005	230 mm1984 · driest 22 mm in 2004	32
April	29.4°C28 Apr 1990	-13.3°C5 Apr 1995	99 mm25 Apr 1983	267 mm2007 · driest 9 mm in 1999	32
May	35.6°C23 May 1992	-4.4°C4 May 1986	91 mm26 May 2005	337 mm2005 · driest 29 mm in 1992	32
June	35.0°C16 Jun 1988	0.0°C3 Jun 1986	84 mm20 Jun 2009	300 mm2006 · driest 38 mm in 1991	31
July	35.6°C3 Jul 2002	2.2°C30 Jul 1989	80 mm14 Jul 1996	214 mm1986 · driest 20 mm in 2001	31
August	35.0°C18 Aug 2002	1.7°C29 Aug 1986	93 mm1 Aug 1985	221 mm1991 · driest 14 mm in 1995	31
September	35.0°C4 Sep 1999	-0.6°C26 Sep 1987	135 mm7 Sep 2008	281 mm2008 · driest 27 mm in 1998	30
October	28.3°C10 Oct 2011	-8.9°C25 Oct 1999	137 mm9 Oct 2005	397 mm2005 · driest 28 mm in 2013	32
November	21.7°C4 Nov 1990	-16.1°C28 Nov 1994	142 mm2 Nov 1988	370 mm1983 · driest 37 mm in 2012	32
December	17.2°C5 Dec 1982	-25.0°C29 Dec 1993	82 mm14 Dec 1983	286 mm1996 · driest 31 mm in 1988	32

Typical days per month at ACADIA NP, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	28	4	6
February	0	0	26	3	5
March	<1	0	25	4	4
April	<1	0	12	4	1
May	3	<1	<1	4	0
June	11	2	0	3	0
July	21	5	0	3	0
August	19	3	0	3	0
September	5	<1	<1	3	0
October	<1	0	4	5	0
November	0	0	15	4	<1
December	0	0	25	5	4

How often, not how much — every day in ACADIA NP’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%	32%	12%	40%	-2.7–2.2°C
February	0%	30%	11%	40%	-1.1–3.6°C
March	1%	31%	13%	37%	3.4–7.0°C
April	4%	32%	13%	40%	9.9–13.4°C
May	28%	35%	14%	46%	16.2–20.5°C
June	59%	31%	12%	37%	21.4–25.1°C
July	74%	25%	9%	29%	23.8–27.8°C
August	75%	24%	8%	25%	24.1–27.3°C
September	50%	26%	11%	31%	19.8–23.2°C
October	10%	30%	13%	38%	12.8–16.5°C
November	<1%	33%	15%	39%	6.7–10.9°C
December	0%	34%	15%	42%	0.9–5.4°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.

1983Each stripe is one year’s mean temperature against the 29-year average. Warmest: 2010. Coolest: 1986.2012

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4980155
NOAA station: USC00170100 · ACADIA NP
Station distance: 17 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 21 usable years
Daylight: Calculated from latitude 44.52°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 17 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 ACADIA NP is what differs

Ellsworth→Bar Harbor→Hancock→Gouldsboro→Tremont→Franklin→

Or put two places side by side: Sullivan vs Ellsworth

Best time to visitSullivan.