USDA Hardiness Zone 10a
Frost Dates for 85258 — Scottsdale, Arizona
Averages from Scottsdale Muni Ap, Az US, the nearest reporting station, 4 miles away.
Plant tender crops after January 6, and expect the first autumn freeze around December 26. That leaves about 353 frost-free days.
- Last spring frost
- January 6
- First fall frost
- December 26
- Growing season
- 353 days
- Hardiness zone
- 10a
50% probability
50% probability
frost-free
30 to 35°F annual low
Planting calendar for 85258
| When | What to do |
|---|---|
| October 28 – November 11 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| November 11 – November 25 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| December 9 – December 23 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| January 6 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by October 3 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by December 12 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| December 26 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 January 6 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Scottsdale, Arizona are past their last freeze. Harvest before December 26, which leaves roughly 353 frost-free days.
ZIP 85258 sits in USDA hardiness zone 10a, meaning the average coldest night of the year falls between 30 to 35°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.