Vernonia, Oregon climate: Normal weather by month, frost dates and records
Vernonia's normal year runs from 31°F December nights to 78°F August afternoons, with 48.0 inches of precipitation and 1 inch of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.7°C, December lows of 0°C, August highs of 26°C, 1,220 mm of precipitation a year.
- NOAA stationVernonia #2
- Station IDUSC00358884
- Location45.87°N 123.19°W
- Elevation625 ft (191 m)
- Population2,428
On October 23, the normal high in Vernonia is 58°F and the normal low 37°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 Vernonia.
- Jan 46° 32°
- Feb 49° 31°
- Mar 54° 34°
- Apr 59° 36°
- May 66° 40°
- Jun 70° 44°
- Jul 77° 47°
- Aug 78° 47°
- Sep 73° 43°
- Oct 61° 38°
- Nov 51° 34°
- Dec 44° 31°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Vernonia each month?
August is the warmest month, with normal highs of 78°F; December the coldest, with normal lows of 31°F. The most precipitation falls in December (8.33 in), the least in July (0.39 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 46°F | 32°F | 38.7°F | 6.94 | 0.3 | 20 | <1 | 17 | 9 h |
| February | 49°F | 31°F | 40.2°F | 5.34 | 0.6 | 17 | <1 | 17 | 10 h 20 min |
| March | 54°F | 34°F | 43.5°F | 5.30 | 0.0 | 20 | <1 | 15 | 11 h 50 min |
| April | 59°F | 36°F | 47.1°F | 3.74 | 0.0 | 17 | <1 | 9 | 13 h 30 min |
| May | 66°F | 40°F | 52.9°F | 2.39 | 0.0 | 12 | <1 | 3 | 14 h 50 min |
| June | 70°F | 44°F | 57.2°F | 1.44 | 0.0 | 10 | 1 | <1 | 15 h 40 min |
| July | 77°F | 47°F | 62.3°F | 0.39 | 0.0 | 4 | 3 | <1 | 15 h 20 min |
| August | 78°F | 47°F | 62.5°F | 0.55 | 0.0 | 4 | 3 | <1 | 14 h 10 min |
| September | 73°F | 43°F | 58.0°F | 1.79 | 0.0 | 8 | 1 | 2 | 12 h 40 min |
| October | 61°F | 38°F | 49.8°F | 4.12 | 0.0 | 15 | <1 | 7 | 11 h |
| November | 51°F | 34°F | 42.4°F | 7.70 | 0.0 | 20 | <1 | 12 | 9 h 30 min |
| December | 44°F | 31°F | 37.8°F | 8.33 | 0.2 | 20 | <1 | 17 | 8 h 40 min |
| Year (annual) | 61°F | 38°F | 49.4°F | 48.03 | 1.1 | 165 | 8 | 99 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | 0°C | 3.7°C | 176 mm | 1 cm |
| February | 10°C | −1°C | 4.6°C | 136 mm | 2 cm |
| March | 12°C | 1°C | 6.4°C | 135 mm | 0 cm |
| April | 15°C | 2°C | 8.4°C | 95 mm | 0 cm |
| May | 19°C | 5°C | 11.6°C | 61 mm | 0 cm |
| June | 21°C | 7°C | 14.0°C | 37 mm | 0 cm |
| July | 25°C | 8°C | 16.8°C | 10 mm | 0 cm |
| August | 26°C | 8°C | 16.9°C | 14 mm | 0 cm |
| September | 23°C | 6°C | 14.4°C | 45 mm | 0 cm |
| October | 16°C | 3°C | 9.9°C | 105 mm | 0 cm |
| November | 10°C | 1°C | 5.8°C | 196 mm | 0 cm |
| December | 7°C | 0°C | 3.2°C | 212 mm | 1 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00358884; 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.
When is the best weather to visit Vernonia?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August 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 USC00358884.
When is the last frost in Vernonia?
In Vernonia, the last spring frost (32°F) comes after May 8 in half of years and after May 29 in one year in ten; the first autumn frost comes before October 1 in half of years and before September 11 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
- May 81 year in 10 after May 29; 9 in 10 after April 18
- First autumn frost, half of years before
- October 11 year in 10 before September 11; 9 in 10 before October 28
NOAA puts the median frost-free season at 144 days, and the season without a hard freeze (28°F) at 191 days.
A hard freeze (28°F) comes after April 12 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Vernonia in zone 8a in ZIP code 97064, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Vernonia's NOAA station is in zone 8a: the coldest night of a typical year reaches 13°F (26 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 USC00358884; 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 in Vernonia?
In a normal year in Vernonia, 8 days a year reach 90°F, 99 nights fall to 32°F or colder and 165 days bring measurable precipitation.
- Days at 90°F or more
- 8a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 99a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 165a normal year
- Days with 1 inch of snow or more
- 1a normal year
The highest temperature in this station's record (since 1967) is 111°F, on June 28, 2021; the lowest is −7°F, on December 20, 1990.
The wettest calendar year on that record is 1996, with 71.16 in; the snowiest season is 1968–69, with 47.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00358884; records: ACIS (NOAA Regional Climate Centers), station USC00358884. Records use complete months only; a month missing more than three days is left out.
How sunny is Vernonia?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Vernonia, 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 much heating and cooling does Vernonia need?
A normal year in Vernonia brings 5,772 heating degree days, 7% more than the median U.S. place (5,373), and 84 cooling degree days, 91% 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 1,476 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 817 | 0 |
| February | 696 | 0 |
| March | 665 | 0 |
| April | 537 | 0 |
| May | 377 | 2 |
| June | 244 | 8 |
| July | 119 | 33 |
| August | 109 | 33 |
| September | 218 | 8 |
| October | 470 | 0 |
| November | 678 | 0 |
| December | 843 | 0 |
| Year (annual) | 5,772 | 84 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00358884. 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.
Has Vernonia been warmer than normal lately?
2025 averaged 50.6°F, 1.3°F above the 1991-2020 normal of 49.4°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 50.0°F | +0.6°F | 48.63 | – |
| 2022 | 50.1°F | +0.7°F | 44.31 | 2.0 |
| 2023 | 50.0°F | +0.6°F | 45.31 | 12.8 |
| 2024 | 50.1°F | +0.7°F | 53.65 | – |
| 2025 | 50.6°F | +1.3°F | 38.86 | – |
Over 48 complete years from 1968 to 2025, the station's annual mean temperature rose at a fitted 4.2°F per century (+0.23°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00358884; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Vernonia's climate compare?
Vernonia is warmer than 30 of the other 104 places with their own NOAA record in Oregon, and wetter than 68. Across the 7,247 U.S. stations with normals, its annual mean of 49.4°F is warmer than 38%.
In the Köppen classification computed from these normals, Vernonia 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.
Questions about Vernonia's climate
What is the coldest month in Vernonia?
December, with a normal high of 44°F and a normal low of 31°F. The warmest is August (78°F by day, 47°F at night).
Does it snow in Vernonia?
Yes: 1 inch in a normal year, falling on 1 days with 0.1 inch or more, the most in February (0.6 inches).
What is the rainiest month in Vernonia?
December, with 8.33 in of precipitation in a normal year; the driest is July with 0.39 in.
What plant hardiness zone is Vernonia in?
The USDA's 2023 map puts Vernonia in zone 8a in ZIP code 97064, the nearest ZIP area. By the same method at Vernonia's NOAA station, the coldest night of a typical year reaches 13°F (26 years, 1991-2020): zone 8a.
How late can frost come in Vernonia?
In half of years the last 32°F night comes after May 8; in one year in ten it comes after May 29. Waiting until May 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- St. Helens, OR16 miles from this station, 51.6°F a year
- Clatskanie, OR17 miles from this station, 50.8°F a year
- Scappoose, OR17 miles from this station, 53.0°F a year
- Longview, WA24 miles from this station, 53.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made