Seattle Temperatures: Averages by Month





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

The average high and low temperatures are listed below monthly and annually for Seattle, 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 60, 70 or 80 °F each month in Seattle, 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 at Seattle—Tacoma International Airport. Everything else here is based on 1991 to 2020 weather, also measured at Sea–Tac.

10-year temperature averages for Seattle, 2010 to 2019
High °F Low °F   High °C Low °C
48 38 January 9 3
48 38 February 9 3
54 40 March 12 5
59 44 April 15 6
66 49 May 19 9
71 53 June 22 12
78 57 July 25 14
79 58 August 26 14
71 54 September 22 12
60 47 October 16 9
52 41 November 11 5
46 37 December 8 3
61 46 Year 16 8
30-year temperature averages for Seattle, 1991 to 2020
High °F Low °F   High °C Low °C
48 38 January 9 3
50 38 February 10 3
54 40 March 12 4
59 43 April 15 6
66 49 May 19 9
71 53 June 22 12
77 57 July 25 14
78 57 August 25 14
72 54 September 22 12
61 47 October 16 8
52 41 November 11 5
47 37 December 8 3
61 46 Year 16 8

Days of Hot Weather in Seattle

Seattle averages only four days a year of temperatures in the 90s Fahrenheit and normally doesn't get any hotter than 100 °F (38 °C).

Nights are equally moderate with minimum temperatures dropping below 70 °F. Just eight times a year, on average does the daily low remain in the 60s.

Days per month in Seattle of at least 60, 70 or 80 °F
  60 °F
16 °C
70 °F
21 °C
80 °F
27 °C
January 0 0 0
February 1 0 0
March 5 0 0
April 11 2 0
May 23 8 2
June 29 14 4
July 31 25 10
August 31 27 10
September 29 16 4
October 14 2 0
November 2 0 0
December 0 0 0
Year 177 94 31

How Often Seattle Has Cold Temperatures

Despite its northern US location, Seattle enjoys mild temperatures. The Pacific Ocean moderates the climate of this coastal city.

Seattle averages just one really frigid day annually, most often in December. On the coldest day of the year the thermometer drops to 20 degrees F or less and the day's highest temperature doesn't break above the freezing point.

Days per month on average in Seattle when the minimum temperature drops to 32 or 40 °F or below
  32 °F
0 °C
40 °F
4 °C
January 7 20
February 6 20
March 2 19
April 0 9
May 0 1
June 0 0
July 0 0
August 0 0
September 0 0
October 0 3
November 3 14
December 7 23
Year 25 110
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.

Seattle Weather
Back to Top