USDA Hardiness Zone 8b
Frost Dates for 98589 — Tenino, Washington
NOAA 1991–2020 normals from Olympia Airport, WA (188 ft), 9 miles northwest.
Updated
In Tenino, the last spring frost (32°F) is around April 29 in half of years and has passed by May 15 in nine years out of ten. The first fall frost comes around October 14, as early as September 28 one year in ten, leaving a typical freeze-free season of 169 days (NOAA, Olympia Airport, WA).
- Last spring frost
- April 29
- First fall frost
- October 14
- Growing season
- 169 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
- 25%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
5 of 20 observed
NOAA normal
Frost risk by date in Tenino
Half of springs at Olympia Airport, WA see their last 32°F night by April 29; only one in ten is past it by April 11, and one in ten still has one after May 15. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 15 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 14 in half of years, as early as September 28 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 18 days later, around November 1; in spring the one-in-ten date for 28°F is April 29, 16 days before the 32°F one. The freeze-free season lasts 169 days in a typical year, shorter than at 69% of the 113 Washington stations; it reaches 195 days one year in ten and falls short of 144 one year in ten. On average 77 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 16 days longer, to about May 15, and return around September 28. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 68%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 30 | May 5 | May 8 | May 12 | May 15 | May 18 | May 22 | May 26 | May 31 |
| 32°F | Apr 11 | Apr 18 | Apr 23 | Apr 27 | Apr 29 | May 2 | May 5 | May 9 | May 15 |
| 28°F | Mar 12 | Mar 22 | Mar 28 | Apr 1 | Apr 5 | Apr 10 | Apr 15 | Apr 21 | Apr 29 |
| 24°F | Feb 7 | Feb 18 | Feb 25 | Mar 1 | Mar 6 | Mar 12 | Mar 18 | Mar 25 | Apr 1 |
| 20°F96% of yrs | Dec 19 | Jan 5 | Jan 22 | Feb 4 | Feb 12 | Feb 17 | Feb 22 | Feb 27 | Mar 8 |
| 16°F68% of yrs | Dec 2 | Dec 12 | Dec 24 | Jan 2 | Jan 17 | Feb 2 | Feb 10 | Feb 16 | Feb 23 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 12 | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 5 | Oct 9 | Oct 14 |
| 32°F | Sep 28 | Oct 3 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 26 | Nov 1 |
| 28°F | Oct 9 | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 5 | Nov 10 | Nov 15 | Nov 24 |
| 24°F | Oct 28 | Nov 2 | Nov 9 | Nov 14 | Nov 20 | Nov 25 | Dec 1 | Dec 7 | Dec 21 |
| 20°F96% of yrs | Nov 6 | Nov 15 | Nov 23 | Nov 30 | Dec 6 | Dec 14 | Dec 26 | Jan 2 | Jan 29 |
| 16°F68% of yrs | Nov 15 | Nov 27 | Dec 4 | Dec 11 | Dec 18 | Dec 28 | Jan 5 | Jan 26 | Feb 15 |
Freeze probabilities 1991–2020 at Olympia Airport, 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 98589 →Compare Tenino with another place →
Weather by month in Tenino
August is the warmest month at Olympia Airport, WA, averaging 78°F by day and 51°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 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 44% of years.
Warmth for growing adds up to 1,723 growing degree days a year (base 50°F), fewer than at 76% of the 113 Washington stations. 28% of them (483) have built up by the end of June, and August adds the most, 442. Precipitation totals 50.8 inches a year, most in November (8.2") and least in July (0.5"); May to September bring 14% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 46 | 33 | 7.8 | 100% | 13 | 2 |
| Feb | 49 | 32 | 5.1 | 100% | 14 | 2 |
| Mar | 54 | 35 | 5.7 | 100% | 13 | 9 |
| Apr | 59 | 38 | 3.7 | 98% | 6 | 39 |
| May | 66 | 43 | 2.3 | 44% | 1 | 159 |
| Jun | 71 | 47 | 1.5 | 0% | 0 | 274 |
| Jul | 78 | 51 | 0.5 | 0% | 0 | 439 |
| Aug | 78 | 51 | 1.0 | 0% | 0 | 442 |
| Sep | 72 | 46 | 2.0 | 14% | <1 | 276 |
| Oct | 60 | 41 | 5.1 | 86% | 4 | 71 |
| Nov | 51 | 36 | 8.2 | 100% | 11 | 11 |
| Dec | 45 | 33 | 7.9 | 100% | 14 | 2 |
Monthly normals 1991–2020 at Olympia Airport, WA (188 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, Centralia, WA, 11 miles southwest of Tenino, has a last frost 7 days earlier (April 22), a first frost 13 days later (October 27), a season 19 days longer.
When it snows in Tenino, Washington
Measurable snow is rare here: only 5 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Centralia, WA, 11.1 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 98589
| When | What to do |
|---|---|
| February 18 – March 4 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 4 – March 18 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 1 – April 15 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 29 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 22 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 30 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 14 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 98589 is 9 miles from Olympia Airport, WA, which stands at 188 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station; its figures are presented in full for 98501 (Olympia). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98589 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.