USDA Hardiness Zone 9a
Frost Dates for 98250 — Friday Harbor, Washington
Averages from Friday Harbor Ap, Wa US, the nearest reporting station, 3.1 miles away.
Plant tender crops after March 26, and expect the first autumn freeze around November 10. That leaves about 230 frost-free days.
- Last spring frost
- March 26
- First fall frost
- November 10
- Growing season
- 230 days
- Hardiness zone
- 9a
50% probability
50% probability
frost-free
20 to 25°F annual low
Planting calendar for 98250
| When | What to do |
|---|---|
| January 15 – January 29 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| January 29 – February 12 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| February 26 – March 12 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| March 26 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by August 18 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by October 27 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| November 10 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 26 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Friday Harbor, Washington are past their last freeze. Harvest before November 10, which leaves roughly 230 frost-free days.
ZIP 98250 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.