USDA Hardiness Zone 6a
Frost Dates for 99166 — Republic, Washington
Averages from Republic, Wa US, the nearest reporting station, 0.9 miles away.
Plant tender crops after May 30, and expect the first autumn freeze around September 10. That leaves about 102 frost-free days.
- Last spring frost
- May 30
- First fall frost
- September 10
- Growing season
- 102 days
- Hardiness zone
- 6a
50% probability
50% probability
frost-free
-10 to -5°F annual low
Planting calendar for 99166
| When | What to do |
|---|---|
| March 21 – April 4 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| April 4 – April 18 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| May 2 – May 16 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| May 30 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by June 18 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by August 27 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| September 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 May 30 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Republic, Washington are past their last freeze. Harvest before September 10, which leaves roughly 102 frost-free days.
ZIP 99166 sits in USDA hardiness zone 6a, meaning the average coldest night of the year falls between -10 to -5°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.