United States · 1991–2020

Best time to visit
South Portland.

August leads for comfortable weather in South Portland: typically 25.8°C by day, 15°C at night, with 91 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortAugust

Typical high25.8°C

Typical low15°C

Rain in August91 mm

Comfort

August

August · July · June

83climate match

Beach

July

July · August · June

62climate match

Outdoors

September

September · May · June

79climate match

The weakest month is January, scoring 5 against August’s 83 — days reach only 0°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° / -9.6°

Feb

51.5° / -8.6°

Mar

55.6° / -3.8°

Apr

2012° / 1.5°

May

5117.7° / 7.1°

Jun

7723° / 12.3°

Jul

7926.2° / 15.8°

Aug

8325.8° / 15°

Sep

7221.6° / 10.8°

Oct

3315.1° / 4.6°

Nov

78.9° / -0.6°

Dec

53.3° / -5.8°

Monthly climate evidence for South Portland — daylight is calculated from latitude, everything else is measured, sea temperature from the nearest open water 10 km away
Month	Day	Night	Rain	Wet days	Sea	Daylight	Comfort	Coverage
January	0°C	-9.6°C	89 mm	8.6	5.3°C	9 h 16	5	Strong coverage
February	1.5°C	-8.6°C	90 mm	8.2	3.8°C	10 h 25	5	Strong coverage
March	5.6°C	-3.8°C	104 mm	9.1	3.4°C	11 h 47	5	Strong coverage
April	12°C	1.5°C	112 mm	9.1	5.3°C	13 h 21	20	Strong coverage
May	17.7°C	7.1°C	93 mm	9.3	8.8°C	14 h 41	51	Strong coverage
June	23°C	12.3°C	105 mm	8.9	12.9°C	15 h 25	77	Strong coverage
July	26.2°C	15.8°C	87 mm	8.5	16.4°C	15 h 08	79	Strong coverage
August	25.8°C	15°C	91 mm	6.8	17.4°C	13 h 59	83	Strong coverage
September	21.6°C	10.8°C	96 mm	7.1	15.5°C	12 h 27	72	Strong coverage
October	15.1°C	4.6°C	133 mm	8.5	12.2°C	10 h 56	33	Strong coverage
November	8.9°C	-0.6°C	108 mm	8.8	9.4°C	9 h 36	7	Strong coverage
December	3.3°C	-5.8°C	114 mm	9.3	7.2°C	8 h 57	5	Strong coverage

What has changed

South Portland runs +1.1°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

+1.8

Feb

+1.4

Mar

+0.9

Apr

+0.7

May

+0.7

Jun

+0.3

Jul

+0.9

Aug

+0.9

Sep

+1.5

Oct

+1.2

Nov

+1.0

Dec

+1.9

August daytime highs, 2011–2025. Last recorded: 26.0°C.

Records at PORTLAND JETPORT, 1940–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	19.4°C6 Jan 2007	-32.2°C19 Jan 1971	90 mm10 Jan 1977	303 mm1979 · driest 7 mm in 2004	86
February	20.0°C21 Feb 2018	-39.4°C16 Feb 1943	97 mm25 Feb 2010	205 mm2008 · driest 1 mm in 1987	86
March	31.1°C31 Mar 1998	-29.4°C4 Mar 1950	88 mm31 Mar 1951	286 mm2010 · driest 21 mm in 1965	86
April	33.3°C28 Apr 2009	-13.3°C4 Apr 1954	132 mm2 Apr 1973	252 mm1973 · driest 7 mm in 1999	86
May	34.4°C31 May 1987	-5.0°C9 May 1956	87 mm2 May 2006	314 mm2006 · driest 13 mm in 1965	86
June	37.2°C24 Jun 2025	0.6°C4 Jun 1944	102 mm20 Jun 1967	233 mm2006 · driest 18 mm in 1941	86
July	37.8°C22 Jul 2011	4.4°C7 Jul 1965	86 mm13 Jul 1996	240 mm2021 · driest 16 mm in 1965	86
August	39.4°C2 Aug 1975	0.6°C31 Aug 1965	197 mm19 Aug 1991	387 mm1991 · driest 7 mm in 1947	85
September	35.0°C7 Sep 1945	-5.0°C30 Sep 1941	190 mm11 Sep 1954	275 mm2008 · driest 8 mm in 1948	85
October	31.1°C7 Oct 1963	-9.4°C28 Oct 1976	298 mm21 Oct 1996	428 mm1996 · driest 7 mm in 1947	85
November	26.1°C6 Nov 2024	-16.1°C24 Nov 1989	128 mm14 Nov 2009	343 mm1983 · driest 11 mm in 1940	86
December	21.7°C6 Dec 2001	-29.4°C31 Dec 1963	89 mm18 Dec 2012	246 mm1969 · driest 25 mm in 1955	86

Typical days per month at PORTLAND JETPORT, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	29	3	8
February	0	0	26	3	7
March	<1	0	25	4	5
April	<1	<1	12	3	1
May	3	<1	<1	3	0
June	11	2	0	3	0
July	21	6	0	3	0
August	19	4	0	2	0
September	6	1	<1	3	0
October	<1	0	6	4	<1
November	0	0	18	4	2
December	0	0	27	4	6

How often, not how much — every day in PORTLAND JETPORT’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%	33%	-3.3–2.4°C
February	0%	28%	11%	32%	-1.4–3.5°C
March	1%	29%	11%	35%	3.0–7.3°C
April	6%	31%	11%	39%	9.9–13.2°C
May	26%	31%	10%	38%	15.6–19.4°C
June	58%	29%	10%	33%	20.6–24.5°C
July	73%	26%	9%	25%	24.3–27.8°C
August	75%	23%	7%	22%	24.1–27.1°C
September	49%	23%	9%	21%	19.6–22.9°C
October	13%	25%	11%	27%	13.3–17.0°C
November	1%	30%	12%	35%	6.6–11.0°C
December	<1%	30%	11%	36%	-0.2–5.4°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.

1941Each stripe is one year’s mean temperature against the 85-year average. Warmest: 2020. Coolest: 1962.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 4979244
NOAA station: USW00014764 · PORTLAND JETPORT
Station distance: 5.1 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 30 usable years
Daylight: Calculated from latitude 43.64°, mid-month, sunrise to sunset including refraction. Not a station measurement.
Sea temperature: NOAA OISST v2.1 1991–2020 monthly climatology, nearest open water 10 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 PORTLAND JETPORT is what differs

Portland→West Scarborough→South Portland Gardens→Westbrook→Old Orchard Beach→Gorham→

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

Best time to visitSouth Portland.

August

July

September

The whole year,without the guesswork.

South Portland runs +1.1°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
South Portland.

The whole year,
without the guesswork.

South Portland runs +1.1°C
on the 1961–1990 baseline.

Nearby, measured,
and named.