USDA Hardiness Zone 8b
Frost Dates for 98606 — Brush Prairie, Washington
NOAA 1991–2020 normals from Battle Ground, WA (284 ft), 4 miles northwest.
Updated
In Brush Prairie, the last spring frost (32°F) is around April 26 in half of years and has passed by May 12 in nine years out of ten. The first fall frost comes around October 16, as early as September 29 one year in ten, leaving a typical freeze-free season of 174 days (NOAA, Battle Ground, WA).
- Last spring frost
- April 26
- First fall frost
- October 16
- Growing season
- 174 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 41%
- Snow per year
- 0.8"
median, 1991–2020
median, 1991–2020
11 of 27 observed
NOAA normal
Frost risk by date in Brush Prairie
Half of springs at Battle Ground, WA see their last 32°F night by April 26; only one in ten is past it by April 5, and one in ten still has one after May 12. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 5 20%, and after May 12 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 74% of the 113 Washington stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 16 in half of years, as early as September 29 one year in ten, and holds off past November 10 one year in ten. A hard freeze of 28°F follows 20 days later, around November 5; in spring the one-in-ten date for 28°F is April 23, 19 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, shorter than at 66% of the 113 Washington stations; it reaches 203 days one year in ten and falls short of 148 one year in ten. On average 70 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 17 days longer, to about May 13, and return around September 30. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 49%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 29 | May 3 | May 6 | May 10 | May 13 | May 17 | May 21 | May 26 | May 31 |
| 32°F | Apr 5 | Apr 13 | Apr 18 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 5 | May 12 |
| 28°F | Mar 4 | Mar 13 | Mar 19 | Mar 25 | Mar 29 | Apr 2 | Apr 8 | Apr 15 | Apr 23 |
| 24°F | Jan 21 | Feb 5 | Feb 15 | Feb 22 | Feb 26 | Mar 1 | Mar 6 | Mar 13 | Mar 24 |
| 20°F89% of yrs | Dec 13 | Dec 31 | Jan 8 | Jan 20 | Jan 31 | Feb 7 | Feb 16 | Feb 22 | Feb 27 |
| 16°F49% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 11 | Sep 18 | Sep 22 | Sep 26 | Sep 30 | Oct 3 | Oct 6 | Oct 11 | Oct 19 |
| 32°F | Sep 29 | Oct 5 | Oct 8 | Oct 13 | Oct 16 | Oct 21 | Oct 26 | Nov 1 | Nov 10 |
| 28°F | Oct 16 | Oct 21 | Oct 27 | Oct 31 | Nov 5 | Nov 10 | Nov 15 | Nov 21 | Nov 30 |
| 24°F | Oct 28 | Nov 5 | Nov 11 | Nov 18 | Nov 24 | Nov 30 | Dec 4 | Dec 13 | Dec 25 |
| 20°F89% of yrs | Nov 11 | Nov 23 | Nov 30 | Dec 5 | Dec 13 | Dec 22 | Dec 29 | Jan 6 | Jan 31 |
| 16°F49% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Battle Ground, WA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 98606 →Compare Brush Prairie with another place →
Weather by month in Brush Prairie
August is the warmest month at Battle Ground, WA, averaging 80°F by day and 50°F at night; December is the coldest at 45°F and 32°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 32% of years.
Warmth for growing adds up to 1,839 growing degree days a year (base 50°F), fewer than at 64% of the 113 Washington stations. 28% of them (517) have built up by the end of June, and August adds the most, 462. Precipitation totals 52.3 inches a year, most in December (8.0") and least in July (0.6"); May to September bring 18% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 46 | 32 | 7.2 | 100% | 15 | 2 |
| Feb | 50 | 32 | 5.3 | 100% | 14 | 2 |
| Mar | 55 | 35 | 5.6 | 100% | 11 | 15 |
| Apr | 60 | 38 | 4.5 | 92% | 3 | 50 |
| May | 67 | 43 | 3.4 | 32% | <1 | 171 |
| Jun | 71 | 47 | 2.3 | 0% | 0 | 277 |
| Jul | 79 | 51 | 0.6 | 0% | 0 | 453 |
| Aug | 80 | 50 | 0.8 | 0% | 0 | 462 |
| Sep | 75 | 46 | 2.2 | 11% | <1 | 303 |
| Oct | 63 | 40 | 4.8 | 76% | 4 | 92 |
| Nov | 52 | 35 | 7.6 | 98% | 9 | 12 |
| Dec | 45 | 32 | 8.0 | 100% | 14 | 2 |
Monthly normals 1991–2020 at Battle Ground, WA (284 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Vancouver 4 NNE, WA, 9 miles southwest of Brush Prairie, has the same 50% last-frost date, a first frost 2 days later (October 18), a season 3 days longer.
When it snows in Brush Prairie, Washington
Measurable snow is rare here: only 11 of 27 winters from 1991 to 2020 recorded 0.1 inch or more at Vancouver 4 NNE, WA, 9.1 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 98606
| When | What to do |
|---|---|
| February 15 – March 1 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 1 – March 15 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 29 – April 12 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 26 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 2 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 16 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 98606 is 4 miles from Battle Ground, WA, which stands at 284 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 98604 (Battle Ground). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98606 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Washington →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.