Metro areas

Gardening in Yuma, AZ

This metro spans USDA zones 9a to 10a, so there is no single zone for Yuma, AZ and anyone who gives you one is rounding. 56% of its ZIP codes are zone 10a; the rest are not.

USDA zones 9a–10a 3 zones across 9 ZIP codes
ZIP codes 9 9 have a NOAA station within range
Weather stations 5 NOAA 1991–2020 normals, across 5,514 sq mi

Which zone you are in depends where you are

Yuma, AZ covers 3 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 56% in zone 10a and wrong for the other 44%. Here is the actual split.

Zone ZIP codes Share  
10a 5 56%
9b 3 33%
9a 1 11%

Zones are published per ZIP code, so yours is exact even though the metro's is not. The hardiness tool will tell you which one you are in.

Your freeze dates

No freeze range is shown for Yuma, AZ, because at least one station here records no freeze at any probability, so there is no date to average. The tools below still answer for individual ZIP codes here, and will say what applies.

Your growing season

NOAA publishes a growing-season length for each station, and across the 5 stations serving Yuma, AZ it runs 288–365 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 105–108 °F , at or above the 90 °F point where cool-season crops bolt and tomato and pepper pollen fails — so midsummer sowings of lettuce and its relatives are worth holding here.

What survives the winter changes across Yuma, AZ

Of 74 perennial fruits, nuts, berries, vegetables and herbs, 46 come through the winter in zone 9a and only 25 in zone 10a. That is a different garden at each end of the same metro.

Zone ZIPs Survive Fail for being too warm
9a 1 46 of 74 25
9b 3 40 of 74 32
10a 5 25 of 74 49

The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.

The 5 stations behind these numbers

Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.

Station NOAA ID Last spring freeze First fall freeze Season
Tacna 3 NE, AZ USC00028396 February 13 December 1 288 days
Yuma 27 Ene, AZ USW00053154 January 11 December 21 347 days
Yuma Mcas, AZ USW00003145 no freeze recorded no freeze recorded 365 days
Yuma Proving Ground, AZ USW00003125 January 4 December 25 361 days
Yuma Quartermaster Depot, AZ USC00029656 January 8 December 28 362 days

These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.

Work out your own dates

Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.

Where these numbers come from

The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.

This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.

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