Portland Troutdale Airport, Oregon climate: Climate normals at a NOAA weather station
Portland Troutdale Airport's normal year runs from 37°F December nights to 82°F August afternoons, with 40.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.6°C, December lows of 3°C, August highs of 28°C, 1,033 mm of precipitation a year.
- NOAA stationPortland Troutdale Airport
- Station IDUSW00024242
- Location45.55°N 122.41°W
- Elevation29 ft (9 m)
On October 23, the normal high in Portland Troutdale Airport is 61°F and the normal low 45°F, and the chance of measurable rain or snow is 52%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Portland Troutdale Airport.
- Jan 47° 37°
- Feb 51° 38°
- Mar 57° 40°
- Apr 62° 43°
- May 69° 49°
- Jun 74° 53°
- Jul 82° 57°
- Aug 82° 57°
- Sep 76° 52°
- Oct 64° 46°
- Nov 53° 42°
- Dec 46° 37°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Portland Troutdale Airport each month?
August is the warmest month, with normal highs of 82°F; December the coldest, with normal lows of 37°F. The most precipitation falls in December (6.15 in), the least in July (0.55 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 47°F | 37°F | 42.0°F | 5.01 | 18 | <1 | 7 | 9 h |
| February | 51°F | 38°F | 44.4°F | 3.71 | 16 | <1 | 6 | 10 h 20 min |
| March | 57°F | 40°F | 48.4°F | 4.41 | 19 | <1 | 4 | 11 h 50 min |
| April | 62°F | 43°F | 52.5°F | 3.58 | 17 | <1 | 1 | 13 h 30 min |
| May | 69°F | 49°F | 58.9°F | 2.91 | 14 | <1 | <1 | 14 h 50 min |
| June | 74°F | 53°F | 63.5°F | 2.11 | 10 | 2 | <1 | 15 h 40 min |
| July | 82°F | 57°F | 69.2°F | 0.55 | 4 | 6 | <1 | 15 h 20 min |
| August | 82°F | 57°F | 69.6°F | 0.63 | 4 | 6 | <1 | 14 h 10 min |
| September | 76°F | 52°F | 64.4°F | 1.75 | 7 | 2 | <1 | 12 h 40 min |
| October | 64°F | 46°F | 55.3°F | 4.02 | 15 | <1 | 1 | 11 h |
| November | 53°F | 42°F | 47.1°F | 5.83 | 18 | <1 | 3 | 9 h 30 min |
| December | 46°F | 37°F | 41.6°F | 6.15 | 19 | <1 | 7 | 8 h 40 min |
| Year (annual) | 64°F | 46°F | 54.7°F | 40.66 | 159 | 16 | 28 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 8°C | 3°C | 5.6°C | 127 mm |
| February | 11°C | 3°C | 6.9°C | 94 mm |
| March | 14°C | 4°C | 9.1°C | 112 mm |
| April | 17°C | 6°C | 11.4°C | 91 mm |
| May | 21°C | 9°C | 14.9°C | 74 mm |
| June | 23°C | 12°C | 17.5°C | 54 mm |
| July | 28°C | 14°C | 20.7°C | 14 mm |
| August | 28°C | 14°C | 20.9°C | 16 mm |
| September | 25°C | 11°C | 18.0°C | 44 mm |
| October | 18°C | 8°C | 12.9°C | 102 mm |
| November | 11°C | 5°C | 8.4°C | 148 mm |
| December | 8°C | 3°C | 5.3°C | 156 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Portland Weather Office (6 miles away), gets 3 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024242; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Portland Troutdale Airport?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (4).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024242.
When is the last frost at Portland Troutdale Airport?
In Portland Troutdale Airport, the last spring frost (32°F) comes after March 16 in half of years and after April 12 in one year in ten; the first autumn frost comes before November 20 in half of years and before October 30 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- March 161 year in 10 after April 12; 9 in 10 after February 18
- First autumn frost, half of years before
- November 201 year in 10 before October 30; 9 in 10 before December 17
NOAA puts the median frost-free season at 250 days, and the season without a hard freeze (28°F) at 311 days.
A hard freeze (28°F) comes after February 14 in half of springs and before December 15 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Portland Troutdale Airport in zone 9a in ZIP code 97024, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 9a: the coldest night of a typical year reaches 22°F (22 complete years).
Frost dates for every NOAA station in Oregon · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00024242; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Portland Troutdale Airport?
In a normal year in Portland Troutdale Airport, 16 days a year reach 90°F (1 of them 100°F or more), 28 nights fall to 32°F or colder and 159 days bring measurable precipitation.
- Days at 90°F or more
- 16a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 28a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 159a normal year
The highest temperature in this station's record (since 1948) is 116°F, on June 28, 2021; the lowest is 3°F, on January 31, 1950.
The wettest calendar year on that record is 1950, with 61.16 in; the snowiest season is 1949–50, with 41.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00024242; records: ACIS (NOAA Regional Climate Centers), station USW00024242. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Portland Troutdale Airport?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds at Portland Troutdale Airport, 3.7 kWh per square metre a day. July is the sunniest month (83%) and December the cloudiest (52%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 54% | 1.2 |
| February | 60% | 2.1 |
| March | 59% | 3.0 |
| April | 63% | 4.3 |
| May | 68% | 5.4 |
| June | 70% | 6.0 |
| July | 83% | 6.8 |
| August | 83% | 5.8 |
| September | 78% | 4.3 |
| October | 67% | 2.6 |
| November | 56% | 1.4 |
| December | 52% | 1.0 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Portland Troutdale Airport record?
A normal year at Portland Troutdale Airport brings 4,155 heating degree days, 23% fewer than the median U.S. place (5,373), and 427 cooling degree days, 53% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,697 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 713 | 0 |
| February | 578 | 0 |
| March | 516 | 0 |
| April | 379 | 3 |
| May | 208 | 19 |
| June | 91 | 46 |
| July | 14 | 144 |
| August | 11 | 154 |
| September | 75 | 57 |
| October | 306 | 4 |
| November | 537 | 0 |
| December | 725 | 0 |
| Year (annual) | 4,155 | 427 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00024242. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Portland Troutdale Airport been warmer than normal?
2023 averaged 56.5°F, 1.8°F above the 1991-2020 normal of 54.7°F. 3 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 56.1°F | +1.4°F | 34.73 |
| 2022 | 55.3°F | +0.6°F | 42.06 |
| 2023 | 56.5°F | +1.8°F | 35.10 |
Source: observed years: ACIS, station USW00024242. A year counts only with all twelve months complete.
How does Portland Troutdale Airport's climate compare?
Portland Troutdale Airport is warmer than 93 of the 105 places with their own NOAA record in Oregon, and wetter than 55. Across the 7,247 U.S. stations with normals, its annual mean of 54.7°F is warmer than 59%.
In the Köppen classification computed from these normals, Portland Troutdale Airport is Csb: temperate, dry-summer, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Portland Troutdale Airport share this climate record?
4 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Gresham, ORalso near: Troutdale (4 mi, 53.4°F a year); Portland (10 mi, 55.1°F a year)111,507 people · 4 mi SW
- Camas, WA27,313 people · 4 mi N
- Fairview, OR10,796 people · 1 mi W
- Wood Village, OR4,722 people · 1 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Portland Troutdale Airport's climate
What is the coldest month at Portland Troutdale Airport?
December, with a normal high of 46°F and a normal low of 37°F. The warmest is August (82°F by day, 57°F at night).
Does it snow at Portland Troutdale Airport?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Portland Weather Office (6 miles away), records 3 inches of snow in a normal year.
What is the rainiest month at Portland Troutdale Airport?
December, with 6.15 in of precipitation in a normal year; the driest is July with 0.55 in.
What plant hardiness zone is Portland Troutdale Airport in?
The USDA's 2023 map puts Portland Troutdale Airport in zone 9a in ZIP code 97024, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 22°F (22 years, 1991-2020): zone 9a.
How late can frost come at Portland Troutdale Airport?
In half of years the last 32°F night comes after March 16; in one year in ten it comes after April 12. Waiting until April 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- Troutdale, OR1 miles from this station, 53.4°F a year
- Portland, OR10 miles from this station, 55.1°F a year
- Skamania Fish Hatchery, WA11 miles from this station, 50.9°F a year
- Vancouver, WA13 miles from this station, 54.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made