Scottsdale, AZ Frost Dates: Last Spring and First Fall Frost

The last spring frost in Scottsdale, AZ comes on January 27 in a typical year, and the first fall frost follows on December 21, leaving a frost-free season of 330 days.

Even odds are a coin toss, so plan around the safer edges: one winter in ten still has a freeze on or after March 5, and one fall in ten has its first freeze by November 28. Compared with the 100-city median of 229 days, Scottsdale gets 101 days extra before frost returns.

The numbers belong to Pinnacle Peak, NOAA station USC00026603, which sits 3.0 miles north of the Census Bureau's internal point for Scottsdale at an elevation of about 2,550 feet.

Last spring frost in Scottsdale

One year in ten has a freeze on or after March 5. In nine years out of ten there is still a freeze on or after December 23, and half of years see one on or after January 27.

A span of 72 days from the 90% date to the 10% date is wide for these pages. Spring in Scottsdale is less predictable than in most of the 100 cities, and the late date is 37 days past the typical one.

When is the first frost in Scottsdale?

Expect the first freeze of fall by December 21 in a typical year. One year in ten brings it by November 28, and nine in ten have had it by January 24.

57 days separate the early and late fall dates, a broad band compared with most cities here, so a fall crop in Scottsdale should be planned against the early date, not the typical one.

How long is the frost-free season in Scottsdale?

Scottsdale has far more frost-free days than the middle of these pages, and slow crops benefit most, as the planting dates below show. Season length swings more here than in most of the 100 cities: 330 days in a typical year, 285 days in a short one, a difference of 45 days.

The season lengths come from NOAA's simulated years, not from subtracting one typical date from the other, so the two will not match to the day. A night at or below 32°F turns up in 91% of years at Pinnacle Peak, so frost is nearly a yearly event; in the other 9% winter passes without one.

28°F dates in Scottsdale

A wide gap separates 32°F from 28°F here: the typical hard freeze arrives 11 days after the first frost in fall (January 1) and leaves 21 days before the last in spring (January 6). Frost-tolerant crops get a long extension at both ends. At the edges, a 28°F night on or after February 8 happens one spring in ten and one by December 6 one fall in ten; the nine-in-ten dates are December 14 and February 2.

Using Scottsdale's frost dates in the garden

In Scottsdale the University of New Hampshire Extension count lands like this, measured from the typical last frost on January 27: lettuce from December 30 to January 6, cabbage on December 30, seed potatoes from January 13 to January 20, then peppers on February 10 and beans from January 27. The University of New Hampshire Extension sheet gives peas no frost count at all; sow them as soon as the soil thaws.

Counting from the late date instead of the typical one adds 37 days before tender crops go out, a big difference in Scottsdale. Gardeners who cannot cover plants on a cold night should take the later date.

Fall crops are counted back from the first frost: NC State Extension's days to harvest plus University of Georgia Extension's harvest allowance of 18 days. All 34 crops in the fall planner have room in Scottsdale, with a last planting day no earlier than July. Of the crops that fit, parsnips is the slowest: 148 days from planting to the early frost, which makes July 3 its last day.

Worked example: planting broccoli for fall in Scottsdale

Take fall broccoli in Scottsdale. NC State Extension lists up to 80 days from transplant to harvest, and University of Georgia Extension adds a harvest allowance of 18 days, so the plants need 98 days before the first frost. Counting back from the typical first frost, December 21, the last planting day is September 14. Counting back from the early date, November 28, it is August 22.

23 days separate the two last days, enough that in Scottsdale the earlier one is worth following.

In spring the same family goes in earlier: counting from January 27, University of New Hampshire Extension puts cabbage transplants out on December 30, weeks ahead of the last frost.

Where Scottsdale's numbers are measured

The nearest usable station stands 3.0 miles north of Scottsdale's internal point, near the city but not in it.

NOAA lists it at about 2,550 feet, higher than 89 and lower than 10 of the 100 stations in this set. Its completeness flag is R, which NOAA uses for a representative record.

Because the Census file has no elevation for Scottsdale, we cannot say how far your yard is above or below this station. When yours is clearly higher or lower, open the nearby stations in the frost dates tool and favor the colder one.

How Scottsdale's frost dates compare

Three cities on these pages lie within a hundred miles of Scottsdale, the nearest Phoenix, AZ at 15 miles, which makes the comparison below a close one. The Phoenix station sits 1,100 feet lower than the Scottsdale one, an elevation difference to keep in mind when you compare the two sets of dates.

• Phoenix, AZ (15 miles, south-west): spring frost ends 19 days sooner than in Scottsdale, and it has 24 days more without frost. Its typical dates are January 8 and December 25, with 354 days frost-free.
• Mesa, AZ (21 miles, south-east): the last frost is 5 days later than in Scottsdale, and the season runs 18 days shorter. Its typical dates are February 1 and December 10, with 312 days frost-free.
• Glendale, AZ, 22 miles to the south-west: last frost January 20, first frost December 15, 331 days frost-free; spring frost ends 7 days sooner than in Scottsdale, and the season is about the same length as Scottsdale's.

Next steps for Scottsdale gardeners

Start with the spring planting planner for the whole crop list counted from these dates, and the fall planting planner for the last planting days. The frost dates tool shows every level of risk at this station, and the hardiness zone lookup covers winter survival for shrubs and perennials.

Every city covered is on the city frost dates index, sorted by state.

Where these numbers come from

NOAA's U.S. Climate Normals for 1991–2020 (doi:10.25921/4ek7-fk11) supply every frost date here, unchanged from the station's record, and NOAA's documentation defines the probabilities. The city and its internal point come from the Census Bureau's 2024 Gazetteer of places, and the ranking by size from the Census Bureau's Vintage 2024 city and town population estimates, which put Scottsdale at 246,170 people.

University of New Hampshire Extension, NC State Extension and University of Georgia Extension supply the planting rules; this page only counts them from the station's dates. The methodology page explains how each figure is checked.

These dates describe odds over many years, not next week's weather. Look at the forecast before you plant, and keep a sheet or row cover ready for a night that does not follow the odds.