Gilbert, AZ planting zone & frost dates

Gilbert is in USDA hardiness zone 9b. The last spring frost usually comes around February 13 and the first fall frost around December 5, for a growing season of about 298 days.

USDA hardiness zone9bavg. extreme winter low 25°F to 30°F
Average last spring frostFebruary 1390% chance of no frost after March 9
Average first fall frostDecember 510% chance of frost by November 18
Growing season298 daysfrost-free days in an average year

Planting calendar for Gilbert

Dates are counted from the average last spring frost (February 13) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.

CropWhen
TomatoesStart seeds indoors: Dec 19 – Jan 2
Transplant outdoors: Feb 20 – Feb 27
PeppersStart seeds indoors: Dec 5 – Dec 19
Transplant outdoors: Feb 27 – Mar 6
EggplantStart seeds indoors: Dec 5 – Dec 19
Transplant outdoors: Feb 27 – Mar 6
BroccoliStart seeds indoors: Dec 5 – Dec 19
Transplant outdoors: Jan 16 – Jan 30
CabbageStart seeds indoors: Dec 5 – Dec 19
Transplant outdoors: Jan 16 – Jan 30
Onions (sets)Plant outdoors: Jan 16 – Jan 30
PeasSow outdoors: Jan 2 – Jan 16
SpinachSow outdoors: Jan 2 – Jan 16
LettuceSow outdoors: Jan 16 – Jan 30
CarrotsSow outdoors: Jan 16 – Jan 30
PotatoesPlant outdoors: Jan 16 – Jan 30
BeansSow outdoors: Feb 20 – Feb 27
Sweet cornSow outdoors: Feb 20 – Feb 27
CucumbersSow outdoors: Feb 20 – Feb 27
Squash & zucchiniSow outdoors: Feb 20 – Feb 27
BasilStart seeds indoors: Jan 2 – Jan 16
Transplant outdoors: Feb 20 – Feb 27

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 10 (8 weeks before the average first fall frost on Dec 5).

Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterJan 12Feb 13Mar 9
First 32°F frost in fall is beforeDec 24Dec 5Nov 18

How to read it: in spring there is a 10% chance of a frost after March 9, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 18. A hard freeze (28°F) usually ends around January 16.

Hardiness zone by ZIP code in Gilbert

Nearby cities

All cities in Arizona → · Other zone 9b cities →

Questions

What growing zone is Gilbert, AZ?

Gilbert is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.

When is the last frost in Gilbert?

The average last spring frost (32°F) in Gilbert is February 13. There is still a 10% chance of frost until March 9.

When can I plant tomatoes in Gilbert?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 20 – Feb 27. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Tempe Asu, AZ (USC00028499), 14.7 km (9.1 mi) from the city center, elevation 356 m, based on 24 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.