Greenly
EN

Phoenix: frost dates

United States

In Phoenix the last spring frost usually comes around 4 February and the first autumn frost around 29 December, which leaves about 328 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 11 February.

Last spring frostaround 4 February
First autumn frostaround 29 December
Frost-free days328 days

Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.

When to sow and plant

CropSow for seedlingsPlant out in a greenhouseOpen ground
Bell Pepper20 November2 February23 February
Chili Pepper6 December18 February11 March
Corn—21 Januarysow 11 February
Cucumber22 December2 February23 February
Eggplant24 November2 February23 February
Green Beans15 December21 January11 February
Melon12 December2 February23 February
Peas—24 Decembersow 14 January
Physalis7 December21 January11 February
Pumpkin15 December21 January11 February
Sweet Corn—21 Januarysow 11 February
Tomato25 November21 January11 February
Watermelon1 January2 February23 February
Zucchini20 December21 January11 February

Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.

Planted in autumn

CropPlant around
Crocus29 November
Daffodil29 November
Garlic29 November
Hyacinth29 November
Lily29 November
Tulip29 November

A month before the first autumn frost, so the roots grow before winter.

Other cities