United States · 1991–2020

Best time to visit
Portland.

September leads for comfortable weather in Portland: typically 23.9°C by day, 12.8°C at night, with 41 mm of rain. Based on measured 1991–2020 NOAA station history.

Best comfortSeptember

Typical high23.9°C

Typical low12.8°C

Rain in September41 mm

Comfort

September

September · August · July

93climate match

Beach

August

August · July · September

77climate match

Outdoors

May

May · June · September

86climate match

The weakest month is January, scoring 5 against September’s 93 — days reach only 8.4°C, 16° 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

58.4° / 3.1°

Feb

1410.3° / 3.7°

Mar

2313.1° / 4.9°

Apr

4116° / 6.7°

May

6720.1° / 9.7°

Jun

8722.8° / 11.9°

Jul

8926.9° / 14.4°

Aug

9027° / 14.8°

Sep

9323.9° / 12.8°

Oct

5117.2° / 8.9°

Nov

1111.3° / 5.4°

Dec

57.7° / 2.9°

Monthly climate evidence for Portland — daylight is calculated from latitude, everything else is measured
Month	Day	Night	Rain	Wet days	Daylight	Comfort	Coverage
January	8.4°C	3.1°C	158 mm	16.2	9 h 04	5	Strong coverage
February	10.3°C	3.7°C	120 mm	12.7	10 h 18	14	Strong coverage
March	13.1°C	4.9°C	124 mm	15.3	11 h 46	23	Strong coverage
April	16°C	6.7°C	91 mm	13.5	13 h 27	41	Strong coverage
May	20.1°C	9.7°C	64 mm	9.5	14 h 52	67	Strong coverage
June	22.8°C	11.9°C	38 mm	6.3	15 h 40	87	Strong coverage
July	26.9°C	14.4°C	10 mm	2.3	15 h 21	89	Strong coverage
August	27°C	14.8°C	14 mm	2.4	14 h 07	90	Strong coverage
September	23.9°C	12.8°C	41 mm	5.3	12 h 28	93	Strong coverage
October	17.2°C	8.9°C	100 mm	10.4	10 h 51	51	Strong coverage
November	11.3°C	5.4°C	163 mm	15.9	9 h 26	11	Strong coverage
December	7.7°C	2.9°C	189 mm	16.9	8 h 43	5	Strong coverage

What has changed

Portland runs +0.2°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

+0.6

Feb

-0.8

Mar

-0.7

Apr

-0.4

May

+0.8

Jun

+0.2

Jul

+1.1

Aug

+1.4

Sep

+0.3

Oct

-0.2

Nov

0.0

Dec

+0.5

September daytime highs, 2011–2025. Last recorded: 24.8°C.

Records at PORTLAND KGW-TV, 1973–2026
Month	Record high	Record low	Wettest day	Wettest / driest month	Years
January	18.3°C18 Jan 2005	-11.1°C13 Jan 2024	64 mm31 Jan 2003	306 mm2006 · driest 7 mm in 1985	52
February	21.7°C28 Feb 1988	-13.3°C3 Feb 1989	65 mm28 Feb 2011	316 mm1996 · driest 25 mm in 1993	52
March	27.8°C26 Mar 2025	-4.4°C3 Mar 1989	51 mm12 Mar 2026	253 mm2012 · driest 44 mm in 1978	53
April	32.2°C19 Apr 2016	-0.6°C1 Apr 2008	34 mm11 Apr 2022	179 mm2003 · driest 16 mm in 1977	53
May	39.4°C28 May 1983	2.2°C6 May 1978	38 mm31 May 1997	134 mm2013 · driest 3 mm in 1992	51
June	45.6°C28 Jun 2021	4.4°C10 Jun 2018	42 mm20 Jun 1991	122 mm2010 · driest 1 mm in 2003	53
July	40.6°C28 Jul 2009	7.2°C22 Jul 1988	32 mm8 Jul 1974	75 mm1983 · driest 0 mm in 2023	52
August	41.1°C10 Aug 1981	7.8°C18 Aug 1973	35 mm25 Aug 1977	91 mm1977 · driest 0 mm in 2022	52
September	39.4°C2 Sep 1988	5.0°C30 Sep 2019	46 mm27 Sep 2021	174 mm2013 · driest 0 mm in 1993	52
October	33.3°C1 Oct 1987	-0.6°C30 Oct 1991	81 mm27 Oct 1994	257 mm2016 · driest 7 mm in 1987	52
November	21.7°C3 Nov 1975	-7.2°C24 Nov 2010	81 mm19 Nov 1996	342 mm1973 · driest 29 mm in 1976	52
December	19.4°C10 Dec 1993	-12.2°C24 Dec 1983	78 mm3 Dec 2007	473 mm2015 · driest 35 mm in 1976	51

Typical days per month at PORTLAND KGW-TV, 1991–2020
Month	Days 25°C+	Days 30°C+	Frost nights	Heavy rain (10 mm+)	Snow days
January	0	0	6	6	<1
February	0	0	3	4	<1
March	0	0	1	4	<1
April	2	<1	0	3	0
May	6	2	0	2	0
June	9	3	0	1	0
July	20	8	0	<1	0
August	21	8	0	<1	0
September	12	4	0	1	0
October	1	0	<1	3	0
November	0	0	2	6	0
December	0	0	6	7	<1

The best month has moved. On the 1961–1990 numbers the strongest month here was June (scoring 91); on 2011–2025 it is September (94). Both are scored the same way, from the same station — only the climate underneath changed.

How often, not how much — every day in PORTLAND KGW-TV’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%	51%	18%	64%	6.0–10.1°C
February	<1%	48%	14%	65%	7.9–12.5°C
March	7%	49%	13%	65%	11.2–15.6°C
April	21%	42%	9%	56%	14.3–18.4°C
May	42%	31%	6%	38%	17.2–21.9°C
June	65%	21%	4%	21%	21.1–25.2°C
July	89%	8%	1%	4%	24.3–28.9°C
August	90%	9%	2%	7%	25.1–28.9°C
September	73%	18%	5%	21%	21.4–25.7°C
October	25%	33%	9%	45%	15.8–19.3°C
November	<1%	54%	19%	74%	9.6–13.2°C
December	0%	53%	21%	70%	5.4–9.5°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.

1974Each stripe is one year’s mean temperature against the 45-year average. Warmest: 2015. Coolest: 2011.2025

The evidence behind this page

Nearby, measured,
and named.

Place identity: GeoNames 5746545
NOAA station: USC00356749 · PORTLAND KGW-TV
Station distance: 1.2 km from the place centre
Climate period: 1991–2020
Minimum month coverage: 29 usable years
Daylight: Calculated from latitude 45.52°, mid-month, sunrise to sunset including refraction. Not a station measurement.
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 KGW-TV is what differs

Milwaukie→Albina→Ardenwald→Arleta→Barnes Heights→Battin→

Or put two places side by side: Portland vs Milwaukie

Best time to visitPortland.

September

August

May

The whole year,without the guesswork.

Portland runs +0.2°Con the 1961–1990 baseline.

Nearby, measured,and named.

Best time to visit
Portland.

The whole year,
without the guesswork.

Portland runs +0.2°C
on the 1961–1990 baseline.

Nearby, measured,
and named.