Phoenix frost dates and planting season

Name: Phoenix
Address: Arizona, United States

When to plant vegetables here. Cover calendars (fleece, cold frame, unheated greenhouse) are on each plant’s when-to-plant page.

Phoenix is frost-free here (frost in fewer than about 1 winter in 10). Growing windows follow temperature limits, not frost dates. Plant cool-season crops after about January 12; wait until about March 23 for warm-season crops.

Frost-free days365all year (frost-free)

Cover calendars (fleece, cold frame, unheated greenhouse) live on each crop’s when-to-plant page.

Weekly possible temperature28 – 117 °F

Frost-free daysall year (frost-free)

Days suitable for warm-season vegetables77 (March 23 – April 26; October 12 – November 22)

Days suitable for cool-season vegetables137 (January 12 – April 5; November 9 – December 31)

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

Frost dates calculated by Plan & Plant from Weather data by Open-Meteo.com (CC BY 4.0). Local frost pockets, valleys and coastal sites can differ by 1–3 weeks.

How we calculated this

Data: ERA5-Land via Open-Meteo, cell 33.45, -112.07, years 2019–2026 (not a 30-year climate normal yet).
Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-6).

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What to plant when

Cool-season vegetables

Earliest outdoor start: January 12

Suitable window: January 12 – April 5; November 9 – December 31

Cool-season crops prefer cooler weather.

Midsummer is often too hot, so suitable weeks split into more than one window.

See cool-season details

Warm-season vegetables

Earliest outdoor start: March 23

Suitable window: March 23 – April 26; October 12 – November 22

Warm-season crops need mild or warm weather and cannot take frost.

Frost kills these crops, and cold snaps set them back.

See warm-season details

Green = usually good weeks to grow; blue or gray = usually too cold for that crop type.

Starter plants for Phoenix

Cool-season

Radish Sow: January 10 – April 2; November 5 – November 20 Planting dates
Arugula Sow: January 10 – April 2 Planting dates
Spinach Sow: January 10 – April 2 Planting dates
Lettuce Sow: January 10 – April 2 Planting dates
Kale Sow: January 10 – March 6 Planting dates
Beet Sow: January 5 – May 24; September 20 – October 6 Planting dates

Warm-season

Cucumber Sow: April 5 – May 30; August 2 – September 5 Planting dates
Green bean Sow: February 22 – May 24 Planting dates
Tomato Transplant: March 24 – May 18 Start indoors, then transplant. Planting dates
Sweet corn Sow: February 22 – June 25; August 2 – September 11 Planting dates

How these dates are judged

Last frost: The typical last spring date when frost is still expected.
First frost: The typical first fall date when frost returns.
Frost-free days: The approximate days between those two dates.
Cool-season vegetables: Crops that prefer cooler weather, such as lettuce, kale, peas, and radish.
Warm-season vegetables: Crops that need warm weather and cannot take frost, such as tomato, pepper, squash, and beans.

Cool-season planting window

Jan 12 – Apr 5; Nov 9 – Dec 31 (137 days)

Warm-season planting window

Mar 23 – Apr 26; Oct 12 – Nov 22 (77 days)

Usually too cold

January 1 – January 11

Weekly temperatures and planting windows

Temperatures across the year for Phoenix, with cool- and warm-season weeks and frost dates.

Possible min to max
Average min to max
Suitable
Tolerable
Too cold
Too hot

Selected week · tap a week or use the arrows

Week 3 · Jan 12 – Jan 18

Average 39 to 66 °F · Possible 28 to 77 °F

Cool season: tolerable

Warm season: too cold

A week is suitable for a crop type when its average low and high sit inside that type's range and its possible readings stay within the frost and heat limits (cool: 28 °F to 81 °F, warm: 32 °F to 90 °F); crossing a limit makes it tolerable, and for warm crops any chance of frost makes it too cold.

Based on average frost dates.

Arizona, United States · 33.45, -112.07 · 2026

Coldest weekly possible temperature28 °F

Hottest weekly possible temperature117 °F

Last expected spring frost

First expected fall frost

Show all 53 weeks