Portland-Hillsboro Airport

KHIO · Oregon, United States

Climate Portland-Hillsboro Airport 2020-2024

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

Calculated from historical METAR data of Portland-Hillsboro Airport (KHIO) between 2020 and 2024.

VFR conditions (%)

Month Average 2024 2023 2022 2021 2020
January 54.8 48 56 55 51 44
February 51.0 55 54 53 48 61
March 64.6 62 48 63 81 66
April 74.7 81 60 74 90 78
May 79.0 85 89 71 82 80
June 82.7 88 91 79 87 73
July 88.6 89 91 84 90 89
August 85.5 87 87 86 93 93
September 76.3 76 86 88 83 61
October 66.1 62 57 62 65 70
November 55.9 51 66 54 55 47
December 48.8 49 59 28 57
Average 70.7 72.5 70.5 70.1 73.0 69.6

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 79.0 73 78 74 69 86
February 75.6 85 79 69 70 74
March 89.1 88 85 91 97 87
April 93.4 96 92 91 98 94
May 94.6 94 95 92 98 94
June 97.3 100 100 97 96 93
July 99.2 98 100 99 99 100
August 96.0 98 95 99 100 99
September 88.9 92 95 98 94 68
October 81.7 81 81 71 81 86
November 74.0 85 82 70 71 65
December 68.2 65 74 63 70
Average 87.7 90.5 87.9 86.5 87.8 85.6

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 8.5 8 9 9 9 10
February 9.2 11 8 11 8 11
March 12.9 14 11 14 13 13
April 16.5 17 15 14 20 18
May 21.6 20 24 18 22 21
June 25.0 25 26 23 29 24
July 29.6 31 30 30 30 28
August 30.1 29 31 32 30 29
September 25.3 26 24 27 26 26
October 18.5 19 19 22 16 19
November 11.2 11 12 9 12 11
December 8.1 10 7 7 9
Average 18.2 19.1 18.3 18.3 18.4 18.2

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 2.1 2 3 1 4 5
February 1.4 4 0 1 2 1
March 2.7 4 2 4 1 2
April 5.0 5 5 4 3 5
May 8.2 7 9 7 7 9
June 10.6 10 10 11 12 11
July 12.4 13 12 14 12 13
August 13.0 13 14 14 13 12
September 10.8 11 11 11 10 12
October 6.2 7 8 8 7 7
November 3.5 5 3 1 6 3
December 1.9 4 0 2 2
Average 6.6 7.2 6.7 6.4 6.5 6.8

Average lowest temperature per day

The minimum temperature is typically observed just before sunrise.

Precipitation (%)

Month Average 2024 2023 2022 2021 2020
January 20.3 32 18 16 19 29
February 19.8 25 22 10 25 9
March 18.2 23 23 14 15 15
April 15.0 14 25 17 4 9
May 9.3 10 4 20 8 13
June 6.1 5 4 10 6 11
July 0.7 1 1 1 0 1
August 0.9 1 3 0 1 1
September 5.4 3 7 2 7 5
October 10.6 15 11 16 13 4
November 16.5 20 10 19 20 22
December 18.6 20 15 26 20
Average 11.1 12.9 11.9 11.4 10.9 10.8

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 4.9 5 6 4 4 7
February 5.0 5 5 4 5 5
March 5.1 5 6 4 5 5
April 5.2 5 5 5 4 4
May 4.0 4 4 5 4 5
June 4.0 4 4 4 4 4
July 3.2 4 3 3 3 4
August 3.1 3 3 3 4 4
September 3.6 3 4 3 4 4
October 3.9 4 4 3 5 4
November 4.3 5 3 5 5 4
December 4.0 3 4 5 5
Average 4.2 4.2 4.1 3.8 4.3 4.4

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 156° 133° 189° 164° 182°
February 165° 178° 112° 199° 217°
March 181° 168° 207° 206° 185°
April 220° 192° 226° 015° 201°
May 283° 018° 210° 290° 192°
June 251° 344° 246° 334° 268°
July 336° 332° 350° 348° 331°
August 304° 346° 338° 326° 328°
September 353° 242° 029° 223° 094°
October 202° 169° 098° 168° 190°
November 175° 211° 137° 182° 198°
December 196° 140° 179° 163°

Prevailing wind direction

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