Boston Temperatures: Averages by Month





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

The average high and low temperatures are listed below monthly and annually for Boston, 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 Boston, 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 recorded at Boston's Logan International Airport.

10-year temperature averages for Boston, 2010 to 2019
High °F Low °F   High °C Low °C
37 23 January 3 -5
40 25 February 4 -4
46 31 March 8 0
58 42 April 14 5
68 52 May 20 11
76 60 June 24 16
84 68 July 29 20
82 66 August 28 19
75 60 September 24 15
64 49 October 18 10
52 38 November 11 3
43 30 December 6 -1
60 45 Year 16 7
30-year temperature averages for Boston, 1981 to 2010
High °F Low °F   High °C Low °C
36 22 January 2 -5
39 25 February 4 -4
45 31 March 7 0
56 41 April 13 5
66 50 May 19 10
76 60 June 24 15
81 65 July 27 19
80 65 August 26 18
72 57 September 22 14
61 47 October 16 8
52 38 November 11 3
41 28 December 5 -2
59 44 Year 15 7

Days of Hot Weather in Boston

Boston averages ten days a summer with temperatures into the 90s Fahrenheit. But temperatures of over 100 degrees are not normal for the city.

Most summer days reach at least 70, while nighttime lows are in the 60s. Highs of 70 degrees can occur in Boston from March to November.

Days per month in Boston 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 1 0 0
April 3 1 0
May 10 3 0
June 22 11 2
July 29 18 4
August 28 15 3
September 18 5 1
October 5 1 0
November 1 0 0
December 0 0 0
Year 116 54 10

How Often Boston Has Cold Temperatures

The thermometer on most winter nights in Boston dips to below freezing. Frost can also show up in March, April and November. The city averages one day a year of extreme cold, when the temperature plummets to zero degrees Fahrenheit or less.

Periodically from December to March, Boston's daytime high never makes it above 32 degrees. On average the city gets 25 days a year when the temperature remains below freezing. Crisp days mostly occur in January, but can happen anytime in winter and even in March.

Days per month on average in Boston when the minimum temperature drops to 10, 20, or 32 °F or below
  10 °F
-12 °C
20 °F
-8 °C
32 °F
0 °C
January 4 12 26
February 1 8 23
March 0 3 15
April 0 0 2
May 0 0 0
June 0 0 0
July 0 0 0
August 0 0 0
September 0 0 0
October 0 0 0
November 0 0 6
December 1 6 21
Year 7 29 92
References

Jay Lawrimore, Ron Ray, Scott Applequist, Bryant Korzeniewski, Matthew Menne. 2016. Global Summary of the Month and Year, Version 1.0. NOAA National Centers for Environmental Information.

NOAA National Centers for Environmental Information. 1981-2010 U.S. Climate Normals. (Data Access. FTP.)

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