USDA Hardiness Zone 9a
Frost Dates for 98087 — Lynnwood, Washington
Averages from Everett Snohomish Ap, Wa US, the nearest reporting station, 4 miles away.
Plant tender crops after March 9, and expect the first autumn freeze around November 17. That leaves about 250 frost-free days.
- Last spring frost
- March 9
- First fall frost
- November 17
- Growing season
- 250 days
- Hardiness zone
- 9a
50% probability
50% probability
frost-free
20 to 25°F annual low
Planting calendar for 98087
| When | What to do |
|---|---|
| December 29 – January 12 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| January 12 – January 26 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| February 9 – February 23 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| March 9 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by August 25 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by November 3 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| November 17 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after March 9 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Lynnwood, Washington are past their last freeze. Harvest before November 17, which leaves roughly 250 frost-free days.
ZIP 98087 sits in USDA hardiness zone 9a, meaning the average coldest night of the year falls between 20 to 25°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.