USDA Hardiness Zone 8a
Frost Dates for 98022 — Enumclaw, Washington
NOAA 1991–2020 normals from Mud Mountain Dam, WA (1,308 ft), 4 miles south.
Updated
In Enumclaw, the last spring frost (32°F) is around April 18 in half of years and has passed by May 10 in nine years out of ten. The first fall frost comes around October 31, as early as October 8 one year in ten, leaving a typical freeze-free season of 196 days (NOAA, Mud Mountain Dam, WA).
- Last spring frost
- April 18
- First fall frost
- October 31
- Growing season
- 196 days
- Hardiness zone
- 8a
50% probability
50% probability
freeze-free, 50%
10 to 15°F (-12.2 to -9.4°C) coldest night
- First snow
- December 11
- Last snow
- February 27
- Winters with snow
- 100%
- Snow per year
- 17.5"
median, 1991–2020
median, 1991–2020
20 of 20 observed
NOAA normal
Frost risk by date in Enumclaw
Half of springs at Mud Mountain Dam, WA see their last 32°F night by April 18; only one in ten is past it by March 28, and one in ten still has one after May 10. Planting tender crops after April 28 leaves a 30% risk of a frost on them, after May 2 20%, and after May 10 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 71% of the 113 Washington stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by October 31 in half of years, as early as October 8 one year in ten, and holds off past November 21 one year in ten. A hard freeze of 28°F follows 17 days later, around November 17; in spring the one-in-ten date for 28°F is April 11, 29 days before the 32°F one. The freeze-free season lasts 196 days in a typical year, longer than at 53% of the 113 Washington stations; it reaches 222 days one year in ten and falls short of 166 one year in ten. On average 79 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 18 days longer, to about May 6, and return around October 12. Nights of 24°F, cold enough to damage hardier plants, come in 96% of winters and 16°F in 35%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 21 | Apr 26 | Apr 30 | May 2 | May 6 | May 10 | May 14 | May 19 | May 26 |
| 32°F | Mar 28 | Apr 2 | Apr 8 | Apr 13 | Apr 18 | Apr 23 | Apr 28 | May 2 | May 10 |
| 28°F | Feb 13 | Feb 25 | Mar 2 | Mar 9 | Mar 15 | Mar 22 | Mar 27 | Apr 2 | Apr 11 |
| 24°F96% of yrs | Dec 29 | Jan 15 | Jan 28 | Feb 4 | Feb 11 | Feb 18 | Feb 22 | Feb 27 | Mar 3 |
| 20°F69% of yrs | Dec 3 | Dec 12 | Dec 23 | Jan 5 | Jan 18 | Jan 30 | Feb 4 | Feb 13 | Feb 20 |
| 16°F35% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 26 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 17 | Oct 21 | Oct 25 | Nov 1 |
| 32°F | Oct 8 | Oct 18 | Oct 23 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 14 | Nov 21 |
| 28°F | Oct 30 | Nov 4 | Nov 9 | Nov 13 | Nov 17 | Nov 22 | Nov 26 | Dec 3 | Dec 11 |
| 24°F96% of yrs | Nov 11 | Nov 19 | Nov 24 | Nov 29 | Dec 3 | Dec 10 | Dec 17 | Dec 31 | Jan 18 |
| 20°F69% of yrs | Nov 23 | Nov 29 | Dec 3 | Dec 8 | Dec 16 | Dec 28 | Jan 5 | Jan 22 | Feb 5 |
| 16°F35% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Mud Mountain Dam, 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 98022 →Compare Enumclaw with another place →
Frost risk through the year in Enumclaw
In Enumclaw, the spring curve drops under 10% on May 10 and the fall curve passes 10% on October 8, 151 days later; that gap is longer than at 50% of the 113 Washington stations with frost dates. The spring risk falls from 90% to 10% over 43 days (March 28 to May 10) and the fall risk climbs from 10% to 90% over 44 days (October 8 to November 21): both ends of the season vary about as much. At Buckley 1 NE, WA, 4 miles southwest, the same gap runs from April 27 to October 8, 13 days longer.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 4 | 77% | 18% |
| Apr 11 | 64% | under 10% |
| Apr 1850% date | 50% | under 10% |
| Apr 25 | 36% | under 10% |
| May 2 | 20% | under 10% |
| May 9 | 11% | under 10% |
Weather by month in Enumclaw
August is the warmest month at Mud Mountain Dam, WA, averaging 76°F by day and 52°F at night; December is the coldest at 45°F and 33°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 79% of years and May still brings one in 23% of years.
Warmth for growing adds up to 1,654 growing degree days a year (base 50°F), fewer than at 83% of the 113 Washington stations. 26% of them (433) have built up by the end of June, and August adds the most, 431. Precipitation totals 60.2 inches a year, most in November (8.0") and least in July (1.5"); May to September bring 26% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 46 | 33 | 7.0 | 100% | 15 | 3 |
| Feb | 47 | 33 | 5.2 | 98% | 14 | 5 |
| Mar | 51 | 35 | 6.6 | 98% | 13 | 13 |
| Apr | 56 | 38 | 5.6 | 79% | 6 | 38 |
| May | 63 | 44 | 5.0 | 23% | 1 | 140 |
| Jun | 67 | 48 | 3.9 | 0% | 0 | 235 |
| Jul | 75 | 52 | 1.5 | 0% | 0 | 414 |
| Aug | 76 | 52 | 1.7 | 0% | 0 | 431 |
| Sep | 70 | 48 | 3.4 | 2% | <1 | 273 |
| Oct | 59 | 42 | 6.0 | 50% | 3 | 85 |
| Nov | 50 | 36 | 8.0 | 96% | 10 | 16 |
| Dec | 45 | 33 | 6.3 | 100% | 17 | 2 |
Monthly normals 1991–2020 at Mud Mountain Dam, WA (1,308 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, Buckley 1 NE, WA, 4 miles southwest of Enumclaw and 623 feet lower, has a last frost 11 days earlier (April 7), a first frost 1 day earlier (October 30), a season 8 days longer.
When it snows in Enumclaw, Washington
The first measurable snow (0.1 inch or more) in Enumclaw usually arrives around December 11, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Palmer 3 ESE, WA, 8.4 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 50 days after the last snow.
Planting calendar for 98022
| When | What to do |
|---|---|
| February 7 – February 21 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 21 – March 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 21 – April 4 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 18 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 8 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 31 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 98022 is 4 miles from Mud Mountain Dam, WA, which stands at 1,308 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98022 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°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.