Portland ME Average Temperatures by Month

The numbers here tell you how hot and cold the weather usually is in Portland, Maine during each month of the year.

The average high and low temperatures are listed below monthly and annually for the city, in both degrees Fahrenheit and Celsius.

Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.

To find out how often it rises over 70, 80 or 90 °F each month in Portland, scroll down farther. There are also monthly and yearly counts of days with cold weather.

The first set of high and low temperatures are averages for 2010 to 2019. Everything else here is based on 1981 to 2010 weather.

10-year temperature averages for Portland, 2010 to 2019
High °F	Low °F		High °C	Low °C
33	16	January	1	-9
36	17	February	2	-8
42	26	March	6	-4
54	35	April	12	2
65	46	May	18	8
73	54	June	23	12
81	62	July	27	16
79	60	August	26	15
72	53	September	22	11
61	42	October	16	6
48	30	November	9	-1
38	22	December	3	-5
57	39	Year	14	4

30-year temperature averages for Portland, 1981 to 2010
High °F	Low °F		High °C	Low °C
31	13	January	0	-10
35	16	February	1	-9
42	25	March	6	-4
53	35	April	12	2
64	44	May	18	7
73	54	June	23	12
79	59	July	26	15
78	58	August	25	15
70	50	September	21	10
59	39	October	15	4
48	31	November	9	-1
37	20	December	3	-6
56	37	Year	13	3

Days of Hot Weather in Portland

Portland doesn't often get really hot, averaging just four days a year with temperatures in the 90s Fahrenheit. And it's not expected to reach 100 °F (38 °C) here. But that 90-degree weather can appear anytime from May to September, although it's most likely to occur in July.

Number of days in Portland of at least 70, 80 or 90 °F
	70 °F 21 °C	80 °F 27 °C	90 °F 32 °C
January	0	0	0
February	0	0	0
March	0	0	0
April	1	0	0
May	7	2	0
June	20	7	1
July	28	13	2
August	28	11	1
September	14	3	0
October	3	0	0
November	0	0	0
December	0	0	0
Year	101	36	4

How Often Portland Has Cold Temperatures

Portland typically has 142 frosty nights a year. Most nights from December to March are below 32 °F and normally seven of those drop to 0 °F (-18 °C) or less.

For an average of 40 days annually the thermometer never rises above freezing. Days that chilly can occur from November to April, including half the days in January.

Days per month on average in Portland when the minimum temperature drops to 32, 20 or 10 °F or below
	10 °F -12 °C	20 °F -8 °C	32 °F 0 °C
January	12	22	30
February	8	17	26
March	2	8	24
April	0	0	10
May	0	0	1
June	0	0	0
July	0	0	0
August	0	0	0
September	0	0	0
October	0	0	7
November	0	2	18
December	5	15	27
Year	28	65	142

Portland Temperatures: Averages by Month

Days of Hot Weather in Portland

How Often Portland Has Cold Temperatures

References

More on Weather in Maine