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 1991 to 2020 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, 1991 to 2020
High °F Low °F   High °C Low °C
37 23 January 3 -5
39 25 February 4 -4
46 31 March 8 0
56 41 April 14 5
67 50 May 19 10
76 60 June 25 15
82 66 July 28 19
80 65 August 27 18
73 58 September 23 15
62 48 October 17 9
52 38 November 11 3
42 29 December 6 -2
59 45 Year 15 7

Days of Hot Weather in Boston

Boston averages 14 days a year with temperatures into the 90s Fahrenheit. But temperatures of over 100 degrees (38 °C) are uncommon for the city, happening an average of just once a decade.

Most summer days reach at least 70, while nighttime lows are in the 60s. Highs of 70 degrees can occur in Boston any month of the year.

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 4 1 0
May 12 4 1
June 23 12 3
July 29 20 6
August 29 18 4
September 20 7 1
October 6 1 0
November 1 0 0
December 0 0 0
Year 125 63 14

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 23 days a year when the temperature remains below freezing. Crisp days mostly occur in January, but can happen anytime in winter.

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 25
February 2 9 22
March 0 3 16
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 7
December 1 5 20
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 (NCEI). Climate Normals.

Boston Weather
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