ClimateAverages

Portland Climate

Maine, United States of America · population 66,881 · 475 weather stations within 200 km · records 1750 to 2025

Average annual daytime high
12.6°C
Warmest month · July
25.8°C
Typical daytime high
Coldest month · January
-10.1°C
Typical overnight low

Portland has an average annual daytime high of 12.6°C, based on the 1951 to 1980 baseline. Its warmest month is July, when highs typically reach 25.8°C, and its coldest is January, with overnight lows near -10.1°C.

Month by month averages

MonthAvg highAvg low
January-1.0°C-10.1°CColdest
February0.2°C-9.7°C
March4.7°C-4.0°C
April11.4°C1.2°C
May17.8°C6.8°C
June22.8°C12.0°C
July25.8°C15.1°CWarmest
August25.0°C14.4°C
September20.6°C10.2°C
October14.7°C4.5°C
November7.9°C0.0°C
December1.0°C-7.0°C

Temperature range across the year

-12°-2°8°18°28°JanFebMarAprMayJunJulAugSepOctNovDec
Daytime high Overnight low
Hottest year on record
2023
+2.2°C vs. 1951–1980
Coldest year on record
1784
-2.4°C vs. 1951–1980

These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.

Is Portland getting hotter?

Since 1900, Portland's average temperature has risen by +2.2°C. Compared to the earliest station records that begin in 1750, warming totals +2.6°C.

7.0°7.7°8.4°9.0°9.7°1951–1980 baseline190019251950197520002025

20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.

Best time to visit
May to September

Daytime highs sit within a comfortable 15°C to 26°C range.

FAQ

What is the average temperature in Portland?

Portland's average annual daytime high is 12.6°C, based on the 1951 to 1980 baseline period. The warmest month is July, with highs averaging 25.8°C, and the coldest is January, with lows averaging -10.1°C.

What is the warmest month in Portland?

July is the warmest month in Portland, with typical daytime highs of 25.8°C.

What is the hottest year on record for Portland?

2023 is the hottest year on record for Portland, running +2.2°C above the 1951 to 1980 baseline.

Is Portland getting hotter?

Yes. Since 1900, Portland has warmed by roughly +2.2°C.

When is the best time to visit Portland?

May to September typically offers the most comfortable daytime highs, in the 15°C to 26°C range.

Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.