Frost dates Washington Tacoma

Frost dates in Tacoma, Washington

Last spring frost Mar 8 First fall frost Nov 14 NOAA 1991-2020

The average last spring frost in Tacoma is Mar 8 and the average first fall frost is Nov 14, measured at TACOMA #1, about 2 miles from the city centre. Below: how sure those dates are, and what to start, sow and set out each week.

Average last spring frostMar 832°F, 50% probability
Average first fall frostNov 1432°F, 50% probability
Days between them251average frost-free season
How sure is that date? NOAA probability levels for a 32°F freeze
ProbabilityFreeze still comes after (spring)First freeze has come by (fall)
90%Feb 15Dec 2
50%Mar 8Nov 14
10%Mar 31Oct 30

Read it like this: in half of years the last 32°F freeze of spring comes after Mar 8, and in 1 year in 10 there is still a freeze after Mar 31. In 1 year in 10 the first fall freeze arrives before Oct 30.

Measured at: TACOMA #1, WA (NOAA station USC00458278), about 2 miles away at 25 ft, 26 years of record in 1991-2020.

Other stations nearby, for comparison:

  • TACOMA NARROWS AP, WA (NOAA station USW00094274), about 6 miles away at 292 ft, 21 years of record in 1991-2020: last spring frost Mar 11, first fall frost Nov 21
  • MCMILLIN RSVR, WA (NOAA station USC00455224), about 12 miles away at 579 ft, 24 years of record in 1991-2020: last spring frost Apr 11, first fall frost Oct 30

Seed-starting schedule for Tacoma, WA

Counted from a last frost date of Mar 8 (the average: a freeze comes later than this in half of years).

  1. Week of Nov 3014 weeks before last frost
    • Start seeds indoorsLeekNov 30 to Dec 14
    • Start seeds indoorsOnionNov 30 to Dec 14
  2. Week of Dec 713 weeks before last frost
    • Start seeds indoorsParsleyDec 7 to Dec 14
  3. Week of Dec 1412 weeks before last frost
    • Start seeds indoorsCeleryDec 14 to Dec 28
    • Start seeds indoorsSpinachDec 14 to Dec 28
  4. Week of Dec 2810 weeks before last frost
    • Start seeds indoorsBroccoliDec 28 to Jan 11
    • Start seeds indoorsBrussels sproutDec 28 to Jan 11
    • Start seeds indoorsCabbageDec 28 to Jan 11
    • Start seeds indoorsKaleDec 28 to Jan 11
    • Start seeds indoorsKohlrabiDec 28 to Jan 11
  5. Week of Jan 49 weeks before last frost
    • Start seeds indoorsLettuceJan 4 to Jan 11
  6. Week of Jan 118 weeks before last frost
    • Start seeds indoorsCauliflowerJan 11 to Jan 25
    • Start seeds indoorsEggplantJan 11 to Jan 25
    • Start seeds indoorsPepperJan 11 to Jan 25
    • Start seeds indoorsSwiss chardJan 11 to Jan 25
  7. Week of Jan 187 weeks before last frost
    • Start seeds indoorsTomatoJan 18 to Feb 1
  8. Week of Jan 256 weeks before last frost
    • Start seeds indoorsBasilJan 25 to Feb 8
    • Set transplants outSpinachJan 25 to Feb 15
  9. Week of Feb 84 weeks before last frost
    • Sow seed outdoorsRadishFeb 8 to Feb 22
    • Sow seed outdoorsSwiss chardfrom Feb 8
    • Sow seed outdoorsTurnipFeb 8 to Feb 22
    • Set transplants outBroccoliFeb 8 to Feb 22
    • Set transplants outBrussels sproutFeb 8 to Feb 22
    • Set transplants outCabbagefrom Feb 8
    • Set transplants outKalefrom Feb 8
    • Set transplants outKohlrabifrom Feb 8
    • Set transplants outLeekfrom Feb 8
    • Set transplants outLettuceFeb 8 to Feb 15
    • Set transplants outOnionfrom Feb 8
  10. Week of Feb 153 weeks before last frost
    • Start seeds indoorsCucumberFeb 15 to Feb 22
    • Set transplants outParsleyFeb 15 to Feb 22
  11. Week of Feb 222 weeks before last frost
    • Start seeds indoorsMelonFeb 22 to Mar 1
    • Start seeds indoorsPumpkinFeb 22 to Mar 1
    • Start seeds indoorsSummer squashFeb 22 to Mar 1
    • Start seeds indoorsWinter squashFeb 22 to Mar 1
    • Start seeds indoorsZucchiniFeb 22 to Mar 1
    • Plant seed potatoes outdoorsPotatoFeb 22 to Mar 1
    • Set transplants outCauliflowerfrom Feb 22
    • Set transplants outSwiss chardfrom Feb 22
  12. Week of Mar 8Last frost week
    • Sow seed outdoorsBeanfrom Mar 8
    • Sow seed outdoorsParsnipfrom Mar 8
    • Set transplants outCeleryfrom Mar 8
  13. Week of Mar 151 week after last frost
    • Plant slips outdoorsSweet potatoMar 15 to Mar 22
    • Set transplants outCucumberMar 15 to Mar 22
    • Set transplants outTomatoMar 15 to Mar 22
  14. Week of Mar 222 weeks after last frost
    • Set transplants outBasilfrom Mar 22
    • Set transplants outEggplantMar 22 to Mar 29
    • Set transplants outMelonfrom Mar 22
    • Set transplants outPepperfrom Mar 22
    • Set transplants outPumpkinfrom Mar 22
    • Set transplants outSummer squashfrom Mar 22
    • Set transplants outWinter squashfrom Mar 22
    • Set transplants outZucchinifrom Mar 22

Not in the city centre? Look up your own ZIP code

More in Washington

Where the numbers come from

Sources and method

Frost dates. U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), NOAA National Centers for Environmental Information (Palecki, Durre, Applequist, Arguez and Lawrimore, 2021). These are 30-year station statistics for 1991 to 2020. "Frost" here means an air temperature of 32°F or lower at the station. We use 6,539 stations that have at least 10 years of record and a published date; 176 more are stations where a freeze is too rare for NOAA to date, and 180 are stations cold enough to have frost risk all year.

Probability level. The headline dates are NOAA's 50% level: in half of years the last spring freeze comes later than that date, and in half of years the first fall freeze comes earlier. The 10% and 90% levels are shown next to them. For tender plants, the 10% spring date is the safer one to plan from: a freeze follows it in only 1 year in 10.

Which station. Your ZIP code is matched to the nearest of those stations by straight-line distance from the ZIP code's centre point (GeoNames, geonames.org, CC BY 4.0; 40,979 ZIP codes in the 50 states and DC). Nearest is not always most alike: a station on a hill, in a valley or by the water can differ from your garden by a week or more. That is why the station's name, distance and elevation are shown with every result, along with two more stations nearby. NOAA makes the same point: the normals are limited between stations as distance grows horizontally and vertically.

Seed-starting offsets. Growing Vegetables: When to Plant Your Vegetable Garden, a fact sheet from University of New Hampshire Extension. It gives each crop's weeks from seed to transplant and when it is safe to set out or sow relative to the last frost. The method is theirs too: take the planting date and count back the seed-to-transplant weeks. Where the fact sheet gives a range of planting dates, the start-indoors dates count back from the earliest one. The figures used, as the fact sheet states them:

  • Basil: Seed to transplant 6-8 weeks; set out 2 weeks after last frost.
  • Bean: Plant seed in garden after last frost.
  • Broccoli: Seed to transplant 4-6 weeks; set out 2-4 weeks before last frost.
  • Brussels sprout: Seed to transplant 4-6 weeks; set out 2-4 weeks before last frost.
  • Cabbage: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Cauliflower: Seed to transplant 4-6 weeks; set out 2 weeks before last frost.
  • Celery: Seed to transplant 10-12 weeks; set out after last frost.
  • Cucumber: Seed to transplant 3-4 weeks; set out 1-2 weeks after last frost.
  • Eggplant: Seed to transplant 8-10 weeks; set out 2-3 weeks after last frost.
  • Kale: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Kohlrabi: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Leek: Seed to transplant 8-10 weeks; set out 4 weeks before last frost.
  • Lettuce: Seed to transplant 4-5 weeks; set out 3-4 weeks before last frost.
  • Melon: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Onion: Seed to transplant 8-10 weeks; set out 4 weeks before last frost.
  • Parsley: Seed to transplant 9-10 weeks; set out 2-3 weeks before last frost.
  • Parsnip: Plant seed in garden after last frost.
  • Pepper: Seed to transplant 8-10 weeks; set out 2 weeks after last frost.
  • Potato: Plant seed potatoes in garden 1-2 weeks before last frost.
  • Pumpkin: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Radish: Plant seed in garden 2-4 weeks before last frost.
  • Spinach: Seed to transplant 4-6 weeks; set out 3-6 weeks before last frost.
  • Summer squash: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Sweet potato: Plant slips in garden 1-2 weeks after last frost.
  • Swiss chard: Seed to transplant 4-6 weeks; set out 2 weeks before last frost; or plant seed in garden 4 weeks before last frost.
  • Tomato: Seed to transplant 6-8 weeks; set out 1-2 weeks after last frost.
  • Turnip: Plant seed in garden 2-4 weeks before last frost.
  • Winter squash: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Zucchini: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.

Not on the calendar. The same fact sheet times these by soil temperature, not by frost date, so they get no date here:

  • Pea: as soon as the soil thaws.
  • Beet: when the soil warms to 45°F.
  • Carrot: when the soil warms to 60°F.
  • Corn: when the soil warms to 60°F.
  • Cucumber, pumpkin, summer squash, winter squash, zucchini: direct-sow when the soil warms to 70°F.

Rutabaga is left out: the fact sheet gives it New Hampshire calendar dates, not a frost offset.

The fact sheet was written for New Hampshire. The offsets are relative to the last frost, so they carry to other places with a spring frost, but where winters are mild many cool-season crops are grown in fall and winter instead. Your state's extension service has the local calendar. Dates are 30-year statistics, not a forecast: check the forecast before setting tender plants out.

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