USDA Hardiness Zone 8a
Frost Dates for 98252 — Granite Falls, Washington
NOAA 1991–2020 normals from Startup 1 E, WA (170 ft), 15 miles south.
Updated
In Granite Falls, the last spring frost (32°F) is around April 15 in half of years and has passed by May 7 in nine years out of ten. The first fall frost comes around October 25, as early as October 5 one year in ten, leaving a typical freeze-free season of 192 days (NOAA, Startup 1 E, WA).
- Last spring frost
- April 15
- First fall frost
- October 25
- Growing season
- 192 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
- Rare
- Last snow
- Rare
- Winters with snow
- 16%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
3 of 19 observed
NOAA normal
Frost risk by date in Granite Falls
Half of springs at Startup 1 E, WA see their last 32°F night by April 15; only one in ten is past it by March 25, and one in ten still has one after May 7. Planting tender crops after April 26 leaves a 30% risk of a frost on them, after May 1 20%, and after May 7 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 25 in half of years, as early as October 5 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 18 days later, around November 12; in spring the one-in-ten date for 28°F is April 11, 26 days before the 32°F one. The freeze-free season lasts 192 days in a typical year, longer than at 51% of the 113 Washington stations; it reaches 222 days one year in ten and falls short of 162 one year in ten. On average 53 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 23 days longer, to about May 8, and return around October 7. Nights of 24°F, cold enough to damage hardier plants, come in 98% of winters and 16°F in 38%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 20 | Apr 26 | May 1 | May 4 | May 8 | May 11 | May 15 | May 20 | May 24 |
| 32°F | Mar 25 | Apr 1 | Apr 6 | Apr 10 | Apr 15 | Apr 20 | Apr 26 | May 1 | May 7 |
| 28°F | Feb 22 | Mar 2 | Mar 8 | Mar 13 | Mar 18 | Mar 22 | Mar 27 | Apr 3 | Apr 11 |
| 24°F98% of yrs | Jan 2 | Jan 22 | Feb 5 | Feb 13 | Feb 19 | Feb 25 | Mar 1 | Mar 7 | Mar 16 |
| 20°F73% of yrs | Dec 5 | Dec 14 | Dec 23 | Jan 2 | Jan 12 | Jan 22 | Feb 3 | Feb 16 | Feb 26 |
| 16°F38% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 22 | Sep 28 | Oct 1 | Oct 5 | Oct 7 | Oct 11 | Oct 15 | Oct 20 | Oct 25 |
| 32°F | Oct 5 | Oct 13 | Oct 17 | Oct 21 | Oct 25 | Oct 28 | Nov 1 | Nov 7 | Nov 15 |
| 28°F | Oct 23 | Oct 29 | Nov 2 | Nov 7 | Nov 12 | Nov 19 | Nov 26 | Dec 1 | Dec 12 |
| 24°F98% of yrs | Nov 7 | Nov 15 | Nov 22 | Nov 29 | Dec 3 | Dec 9 | Dec 18 | Dec 29 | Jan 14 |
| 20°F73% of yrs | Nov 18 | Nov 27 | Dec 2 | Dec 7 | Dec 14 | Dec 20 | Dec 30 | Jan 8 | Jan 29 |
| 16°F38% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Startup 1 E, 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 98252 →Compare Granite Falls with another place →
Weather by month in Granite Falls
August is the warmest month at Startup 1 E, WA, averaging 78°F by day and 51°F at night; December is the coldest at 47°F and 34°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 75% of years and May still brings one in 22% of years.
Warmth for growing adds up to 1,904 growing degree days a year (base 50°F), fewer than at 57% of the 113 Washington stations. 30% of them (572) have built up by the end of June, and August adds the most, 462. Precipitation totals 68.3 inches a year, most in November (9.8") and least in July (1.5"); May to September bring 23% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 47 | 34 | 8.9 | 100% | 12 | 5 |
| Feb | 51 | 34 | 5.9 | 99% | 11 | 7 |
| Mar | 55 | 36 | 6.8 | 99% | 7 | 20 |
| Apr | 60 | 39 | 5.9 | 75% | 2 | 61 |
| May | 67 | 44 | 5.0 | 22% | <1 | 187 |
| Jun | 71 | 49 | 3.8 | 0% | 0 | 293 |
| Jul | 78 | 52 | 1.5 | 0% | 0 | 453 |
| Aug | 78 | 51 | 1.7 | 0% | 0 | 462 |
| Sep | 73 | 47 | 3.5 | 6% | 0 | 298 |
| Oct | 62 | 42 | 7.1 | 65% | 2 | 99 |
| Nov | 52 | 37 | 9.8 | 95% | 7 | 18 |
| Dec | 47 | 34 | 8.4 | 100% | 11 | 3 |
Monthly normals 1991–2020 at Startup 1 E, WA (170 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, Darrington Rs, WA, 17 miles northeast of Granite Falls and 380 feet higher, has a last frost 1 day later (April 16), a first frost 2 days earlier (October 23), a season 2 days shorter.
When it snows in Granite Falls, Washington
Measurable snow is rare here: only 3 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Startup 1 E, WA, 14.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 98252
| When | What to do |
|---|---|
| February 4 – February 18 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 18 – March 4 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 18 – April 1 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 15 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 2 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 25 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 98252 is 15 miles from Startup 1 E, WA, which stands at 170 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98252 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.