Seattle-Tacoma International Airport

KSEA · Washington, United States

Climate Seattle-Tacoma International Airport 2020-2024

Climate and trends: average temperature, flight conditions, precipitation, wind speed and direction.

Calculated from historical METAR data of Seattle-Tacoma International Airport (KSEA) between 2020 and 2024.

VFR conditions (%)

Month Average 2024 2023 2022 2021 2020
January 65.5 64 61 44 73 54
February 55.1 56 64 47 45 57
March 72.3 76 70 61 76 67
April 77.6 73 78 88 81
May 74.0 70 77 70 79
June 74.7 69 73 85 78
July 80.2 83 83 74 77
August 76.9 79 81 76 84
September 78.6 78 86 83 63
October 66.9 66 59 74 57
November 67.1 76 62 63 68
December 59.9 48 56 48 71
Average 70.8 65.5 70.0 68.4 72.2 70.4

VFR conditions during daylight period

Percentage of observations where the VFR minimums for ceiling and visibility are met: visibility of 5 mi or more and a ceiling of 3,000 ft or more. Only observations between sunrise and sunset are taken into account.

Marginal VFR conditions (%)

Month Average 2024 2023 2022 2021 2020
January 87.0 86 90 68 91 88
February 85.5 84 93 81 86 86
March 94.3 97 96 90 95 93
April 95.1 96 95 98 96
May 92.9 91 96 91 96
June 92.9 90 91 96 93
July 94.0 93 98 87 92
August 92.9 94 95 94 97
September 91.9 96 94 97 70
October 85.2 82 79 91 79
November 86.6 90 82 84 92
December 83.0 75 77 84 89
Average 90.4 89.0 90.6 88.0 91.3 89.5

Marginal VFR conditions or better during daylight period

Percentage of observations where the MVFR minimums for ceiling and visibility are met: visibility of 3⅛ mi or more and a ceiling of 1,000 ft or more. Only observations between sunrise and sunset are taken into account.

Maximum temperatures (°C)

Month Average 2024 2023 2022 2021 2020
January 8.7 8 9 8 9 10
February 8.2 10 8 9 8 10
March 11.8 12 11 12 12 11
April 15.0 13 13 18 16
May 20.1 22 16 19 21
June 22.8 23 21 26 22
July 26.7 27 27 27 25
August 26.9 27 28 26 26
September 22.4 22 24 22 24
October 16.0 17 19 15 16
November 10.7 10 9 11 11
December 8.0 10 5 5 10
Average 15.7 9.9 16.7 16.2 16.4 16.7

Average highest temperature per day

The maximum temperature is typically observed some hours after noon.

Minimum temperatures (°C)

Month Average 2024 2023 2022 2021 2020
January 3.7 3 4 3 5 5
February 2.8 5 2 3 3 4
March 4.4 5 3 5 4 4
April 6.6 6 5 7 7
May 10.1 11 8 9 11
June 12.3 11 12 14 12
July 14.3 14 14 14 14
August 15.1 16 15 14 15
September 12.9 12 13 12 12
October 8.6 8 10 9 10
November 5.4 5 3 6 6
December 3.5 5 1 2 4
Average 7.8 4.2 8.2 7.9 8.1 8.6

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Precipitation (%)

Month Average 2024 2023 2022 2021 2020
January 21.1 30 19 18 20 36
February 20.3 24 13 17 24 12
March 14.1 13 10 17 12 14
April 13.8 20 13 5 6
May 8.4 5 18 6 13
June 7.4 7 13 7 10
July 2.3 0 2 1 5
August 1.9 5 1 1 3
September 6.0 8 3 9 6
October 11.0 12 9 15 4
November 17.9 6 23 26 20
December 22.0 27 24 27 18
Average 12.7 22.0 10.6 12.4 11.6 11.4

Precipitation during daylight period

Percentage of observations with observed rain, drizzle, snow or hail. Only observations between sunrise and sunset are taken into account.

Wind speed (knots)

Month Average 2024 2023 2022 2021 2020
January 7.1 7 7 6 6 9
February 8.1 7 9 7 9 8
March 7.6 7 8 7 7 8
April 8.0 8 8 7 7
May 6.6 6 7 7 7
June 6.8 7 7 7 7
July 6.3 6 6 6 7
August 6.4 6 7 7 6
September 6.7 7 7 7 7
October 6.9 6 6 8 7
November 7.3 6 7 8 8
December 7.0 6 6 9 7
Average 7.0 7.0 6.8 6.8 7.3 7.2

Average wind speed

Excluding wind gusts. Only observations between sunrise and sunset are taken into account.

Prevailing wind direction

Month 2024 2023 2022 2021 2020
January 145° 133° 187° 162° 181°
February 167° 190° 203° 192° 205°
March 211° 204° 216° 206° 219°
April 206° 215° 249° 229°
May 265° 215° 246° 234°
June 250° 248° 252° 222°
July 250° 261° 258° 246°
August 294° 255° 244° 267°
September 231° 326° 231° 285°
October 102° 226° 182° 217°
November 195° 046° 188° 195°
December 158° 068° 188° 182°

Prevailing wind direction

Average wind direction, weighed by wind speed. Only observations between sunrise and sunset are taken into account.