USDA Hardiness Zone 8b
Frost Dates for 98626 — Kelso, Washington
NOAA 1991–2020 normals from Longview, WA (12 ft), 2 miles west.
Updated
In Kelso, the last spring frost (32°F) is around April 8 in half of years and has passed by May 2 in nine years out of ten. The first fall frost comes around November 5, as early as October 17 one year in ten, leaving a typical freeze-free season of 210 days (NOAA, Longview, WA).
- Last spring frost
- April 8
- First fall frost
- November 5
- Growing season
- 210 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
- 20%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
4 of 20 observed
NOAA normal
Frost risk by date in Kelso
Half of springs at Longview, WA see their last 32°F night by April 8; only one in ten is past it by March 11, and one in ten still has one after May 2. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 26 20%, and after May 2 10%. The 24 days between the even-odds date and the one-in-ten date is wider than at 86% 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 November 5 in half of years, as early as October 17 one year in ten, and holds off past November 28 one year in ten. A hard freeze of 28°F follows 19 days later, around November 24; in spring the one-in-ten date for 28°F is April 4, 28 days before the 32°F one. The freeze-free season lasts 210 days in a typical year, longer than at 67% of the 113 Washington stations; it reaches 244 days one year in ten and falls short of 177 one year in ten. On average 41 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 25 days longer, to about May 3, and return around October 21. Nights of 24°F, cold enough to damage hardier plants, come in 93% of winters and 16°F in 22%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Apr 22 | Apr 27 | Apr 30 | May 3 | May 7 | May 10 | May 16 | May 24 |
| 32°F | Mar 11 | Mar 21 | Mar 29 | Apr 2 | Apr 8 | Apr 14 | Apr 20 | Apr 26 | May 2 |
| 28°F | Feb 6 | Feb 17 | Feb 24 | Feb 28 | Mar 6 | Mar 11 | Mar 17 | Mar 27 | Apr 4 |
| 24°F93% of yrs | Dec 14 | Jan 1 | Jan 14 | Jan 30 | Feb 10 | Feb 15 | Feb 21 | Feb 27 | Mar 3 |
| 20°F59% of yrs | Dec 2 | Dec 10 | Dec 19 | Dec 30 | Jan 6 | Jan 22 | Feb 4 | Feb 14 | Feb 22 |
| 16°F22% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 2 | Oct 7 | Oct 13 | Oct 17 | Oct 21 | Oct 26 | Oct 30 | Nov 3 | Nov 10 |
| 32°F | Oct 17 | Oct 24 | Oct 29 | Nov 1 | Nov 5 | Nov 10 | Nov 15 | Nov 21 | Nov 28 |
| 28°F | Oct 31 | Nov 7 | Nov 13 | Nov 19 | Nov 24 | Nov 28 | Dec 3 | Dec 10 | Dec 20 |
| 24°F93% of yrs | Nov 13 | Nov 23 | Nov 29 | Dec 5 | Dec 11 | Dec 20 | Dec 26 | Jan 4 | Jan 29 |
| 20°F59% of yrs | Nov 25 | Dec 1 | Dec 7 | Dec 12 | Dec 20 | Dec 26 | Jan 2 | Jan 24 | Feb 12 |
| 16°F22% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Longview, 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 98626 →Compare Kelso with another place →
Weather by month in Kelso
August is the warmest month at Longview, WA, averaging 80°F by day and 53°F at night; December is the coldest at 47°F and 35°F. A freezing night is all but certain in every month from December 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 58% of years and May still brings one in 12% of years.
Warmth for growing adds up to 2,268 growing degree days a year (base 50°F), more than at 62% of the 113 Washington stations. 30% of them (686) have built up by the end of June, and August adds the most, 522. Precipitation totals 48.0 inches a year, most in November (7.2") and least in July (0.6"); May to September bring 19% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 48 | 35 | 6.5 | 98% | 10 | 4 |
| Feb | 52 | 35 | 4.8 | 96% | 9 | 6 |
| Mar | 57 | 38 | 4.9 | 91% | 5 | 31 |
| Apr | 62 | 40 | 4.1 | 58% | 2 | 83 |
| May | 69 | 45 | 3.1 | 12% | <1 | 226 |
| Jun | 73 | 50 | 2.0 | 1% | <1 | 336 |
| Jul | 79 | 53 | 0.6 | 0% | 0 | 507 |
| Aug | 80 | 53 | 1.0 | 0% | 0 | 522 |
| Sep | 76 | 50 | 2.3 | 0% | 0 | 380 |
| Oct | 64 | 44 | 4.4 | 37% | 1 | 150 |
| Nov | 53 | 39 | 7.2 | 89% | 5 | 21 |
| Dec | 47 | 35 | 7.1 | 100% | 9 | 3 |
Monthly normals 1991–2020 at Longview, WA (12 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, Clatskanie, OR, 16 miles west of Kelso, has a last frost 16 days later (April 24), a first frost 12 days earlier (October 24), a season 26 days shorter.
When it snows in Kelso, Washington
Measurable snow is rare here: only 4 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Longview, WA, 1.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 98626
| When | What to do |
|---|---|
| January 28 – February 11 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 11 – February 25 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 11 – March 25 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 8 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 5 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 98626 is 2 miles from Longview, WA, which stands at 12 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 98632 (Longview). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98626 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.