Headworks Portland Water B, Oregon climate: Climate normals at a NOAA weather station
Headworks Portland Water B's normal year runs from 35°F December nights to 78°F August afternoons, with 79.0 inches of precipitation and 3 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.8°C, December lows of 2°C, August highs of 25°C, 2,006 mm of precipitation a year.
- NOAA stationHeadworks Portland Water B
- Station IDUSC00353770
- Location45.45°N 122.15°W
- Elevation748 ft (228 m)
On October 23, the normal high in Headworks Portland Water B is 57°F and the normal low 44°F, and the chance of measurable rain or snow is 58%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Headworks Portland Water B.
- Jan 44° 35°
- Feb 47° 36°
- Mar 52° 37°
- Apr 57° 41°
- May 64° 46°
- Jun 69° 50°
- Jul 77° 54°
- Aug 78° 54°
- Sep 72° 51°
- Oct 60° 45°
- Nov 49° 40°
- Dec 43° 35°
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 Headworks Portland Water B each month?
August is the warmest month, with normal highs of 78°F; December the coldest, with normal lows of 35°F. The most precipitation falls in December (11.67 in), the least in July (0.95 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 44°F | 35°F | 39.5°F | 10.26 | 0.7 | 22 | <1 | 9 | 9 h |
| February | 47°F | 36°F | 41.6°F | 7.95 | 1.2 | 18 | <1 | 7 | 10 h 20 min |
| March | 52°F | 37°F | 44.6°F | 8.50 | 0.2 | 21 | <1 | 4 | 11 h 50 min |
| April | 57°F | 41°F | 48.7°F | 7.34 | 0.0 | 20 | <1 | 1 | 13 h 30 min |
| May | 64°F | 46°F | 54.8°F | 5.72 | 0.0 | 16 | <1 | <1 | 14 h 50 min |
| June | 69°F | 50°F | 59.3°F | 3.96 | 0.0 | 12 | 1 | <1 | 15 h 40 min |
| July | 77°F | 54°F | 65.2°F | 0.95 | 0.0 | 5 | 3 | <1 | 15 h 20 min |
| August | 78°F | 54°F | 65.9°F | 1.20 | 0.0 | 5 | 4 | <1 | 14 h 10 min |
| September | 72°F | 51°F | 61.3°F | 3.42 | 0.0 | 9 | 2 | <1 | 12 h 40 min |
| October | 60°F | 45°F | 52.6°F | 7.37 | 0.0 | 17 | <1 | <1 | 11 h |
| November | 49°F | 40°F | 44.3°F | 10.62 | 0.2 | 21 | <1 | 3 | 9 h 30 min |
| December | 43°F | 35°F | 39.1°F | 11.67 | 0.6 | 23 | <1 | 8 | 8 h 40 min |
| Year (annual) | 59°F | 44°F | 51.4°F | 78.96 | 2.9 | 190 | 10 | 32 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 7°C | 2°C | 4.2°C | 261 mm | 2 cm |
| February | 8°C | 2°C | 5.3°C | 202 mm | 3 cm |
| March | 11°C | 3°C | 7.0°C | 216 mm | 1 cm |
| April | 14°C | 5°C | 9.3°C | 186 mm | 0 cm |
| May | 18°C | 8°C | 12.7°C | 145 mm | 0 cm |
| June | 21°C | 10°C | 15.2°C | 101 mm | 0 cm |
| July | 25°C | 12°C | 18.4°C | 24 mm | 0 cm |
| August | 25°C | 12°C | 18.8°C | 30 mm | 0 cm |
| September | 22°C | 11°C | 16.3°C | 87 mm | 0 cm |
| October | 16°C | 7°C | 11.4°C | 187 mm | 0 cm |
| November | 10°C | 4°C | 6.8°C | 270 mm | 1 cm |
| December | 6°C | 2°C | 3.9°C | 296 mm | 2 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353770; 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 Headworks Portland Water B?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (5).
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 USC00353770.
When is the last frost at Headworks Portland Water B?
In Headworks Portland Water B, the last spring frost (32°F) comes after March 27 in half of years and after April 20 in one year in ten; the first autumn frost comes before November 18 in half of years and before October 26 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 271 year in 10 after April 20; 9 in 10 after February 26
- First autumn frost, half of years before
- November 181 year in 10 before October 26; 9 in 10 before December 10
NOAA puts the median frost-free season at 239 days, and the season without a hard freeze (28°F) at 303 days.
A hard freeze (28°F) comes after February 14 in half of springs and before December 9 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Headworks Portland Water B in zone 8b in ZIP code 97019, 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 21°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Oregon · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00353770; 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 Headworks Portland Water B?
In a normal year in Headworks Portland Water B, 10 days a year reach 90°F (1 of them 100°F or more), 32 nights fall to 32°F or colder and 190 days bring measurable precipitation.
- Days at 90°F or more
- 10a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 32a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 190a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1899) is 110°F, on July 13, 1935; the lowest is 1°F, on January 12, 1909.
The wettest calendar year on that record is 1933, with 137.82 in; the snowiest season is 1936–37, with 100.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00353770; records: ACIS (NOAA Regional Climate Centers), station USC00353770. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Headworks Portland Water B?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds at Headworks Portland Water B, 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 Headworks Portland Water B record?
A normal year at Headworks Portland Water B brings 5,144 heating degree days, 4% fewer than the median U.S. place (5,373), and 209 cooling degree days, 77% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,960 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 789 | 0 |
| February | 657 | 0 |
| March | 631 | 0 |
| April | 490 | 1 |
| May | 321 | 7 |
| June | 189 | 18 |
| July | 64 | 72 |
| August | 51 | 78 |
| September | 142 | 31 |
| October | 387 | 3 |
| November | 621 | 0 |
| December | 803 | 0 |
| Year (annual) | 5,144 | 209 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353770. 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 Headworks Portland Water B been warmer than normal?
2025 averaged 52.2°F, 0.8°F above the 1991-2020 normal of 51.4°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 51.5°F | +0.1°F | 71.29 | 18.7 |
| 2022 | 51.0°F | −0.4°F | 83.71 | 6.0 |
| 2023 | 51.9°F | +0.5°F | 69.38 | 10.6 |
| 2024 | 51.7°F | +0.3°F | 80.21 | – |
| 2025 | 52.2°F | +0.8°F | 75.70 | 3.3 |
Over 94 complete years from 1900 to 2025, the station's annual mean temperature rose at a fitted 2.0°F per century (+0.11°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00353770; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Headworks Portland Water B's climate compare?
Headworks Portland Water B is warmer than 45 of the 105 places with their own NOAA record in Oregon, and wetter than 90. Across the 7,247 U.S. stations with normals, its annual mean of 51.4°F is warmer than 47%.
In the Köppen classification computed from these normals, Headworks Portland Water B 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 Headworks Portland Water B share this climate record?
Mount Hood Villages has no NOAA station with 1991-2020 normals of its 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.
- Mount Hood Villages, OR5,139 people · 12 mi SE
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 Headworks Portland Water B's climate
What is the coldest month at Headworks Portland Water B?
December, with a normal high of 43°F and a normal low of 35°F. The warmest is August (78°F by day, 54°F at night).
Does it snow at Headworks Portland Water B?
Yes: 3 inches in a normal year, falling on 2 days with 0.1 inch or more, the most in February (1.2 inches).
What is the rainiest month at Headworks Portland Water B?
December, with 11.67 in of precipitation in a normal year; the driest is July with 0.95 in.
What plant hardiness zone is Headworks Portland Water B in?
The USDA's 2023 map puts Headworks Portland Water B in zone 8b in ZIP code 97019, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 21°F (30 years, 1991-2020): zone 9a.
How late can frost come at Headworks Portland Water B?
In half of years the last 32°F night comes after March 27; in one year in ten it comes after April 20. Waiting until April 20 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- Skamania Fish Hatchery, WA12 miles from this station, 50.9°F a year
- Troutdale, OR14 miles from this station, 53.4°F a year
- Portland Troutdale Airport, OR14 miles from this station, 54.7°F a year
- Estacada, OR15 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