Place guide
Planting zones in Sierra Vista-Douglas, AZ
This metro spans USDA zones 8a to 8b, so there is no single zone for Sierra Vista-Douglas, AZ and anyone who gives you one is rounding. 76% of its ZIP codes are zone 8b; the rest are not.
Your ZIP code
Get the exact answer for your address
Everything above describes Sierra Vista-Douglas, AZ as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.
Sierra Vista-Douglas, AZ does not have one planting answer
Its own weather stations disagree about 19 of the 32 crops in this table right now, so any single list would be wrong for part of the metro area. That is not a gap in the data — it is what the data says.
- Shortest season
- 187 days
CASCABEL, AZ US (USC00021330) - Longest season
- 264 days
TOMBSTONE, AZ US (USC00028619)
77 days of growing season separate those two stations, and both serve ZIP codes in Sierra Vista-Douglas, AZ. The ZIP lookup above answers for one address instead of averaging a place that has no average.
Why the hardiness zone does not settle this
A USDA zone is a winter-minimum statistic. It was never a growing-season one, and it does not behave like one: within a single zone the growing season runs a median 54 days wider at the 10th–90th percentile, and annual growing degree days vary by 2.02×.
The zones also overlap rather than stack — 30% of zone 6b freezes before the median zone 6a station. The zone tells you what survives your winter; the station tells you what finishes before your autumn.
All 13 stations agreeAt least one station
Every one of the 13 NOAA stations serving this metro area counts April 24 – October 27 as growing season (186 days). Widening to any single station gives March 4 – November 29 (270 days).
That is a 84-day difference inside one metro area — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.
Which zone you are in depends where you are
Sierra Vista-Douglas, AZ covers 2 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 76% in zone 8b and wrong for the other 24%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 8b | 16 | 76% | |
| 8a | 5 | 24% |
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
Those are the earliest and latest medians among the 13 stations serving this metro — not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.
The spread is the point. Even in a metro that is one hardiness zone throughout, its stations disagree about the last spring freeze. Hardiness zone and frost date measure different things — a zone is the average annual coldest night, a freeze date is when the season turns — and a place can be uniform in one and varied in the other. Use the tools below with your own ZIP rather than the ends of this range.
Your growing season
NOAA publishes a growing-season length for each station, and across the 13 stations serving Sierra Vista-Douglas, AZ it runs 187–264 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 87–98 °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. Summer rain over the same months runs 5.2–10.2" across those 13 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 51% of it, so expect to make up the rest. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 94 °F summer afternoon drying the soil faster than a cool one.
When to start seeds in Sierra Vista-Douglas, AZ
Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 13 stations — the earliest and latest that job falls anywhere in the metro — because no one station speaks for the whole area.
| Crop | Job | When | Offset |
|---|---|---|---|
| Green Onions | Start indoors | January 7 – February 27 | 8 weeks before |
| Peppers | Start indoors | January 7 – February 27 | 8 weeks before |
| Broccoli | Start indoors | January 21 – March 13 | 6 weeks before |
| Cabbage | Start indoors | January 21 – March 13 | 6 weeks before |
| Collards | Start indoors | January 21 – March 13 | 6 weeks before |
| Kale | Start indoors | January 21 – March 13 | 6 weeks before |
| Leaf Lettuce | Start indoors | January 21 – March 13 | 6 weeks before |
| Peas | Direct sow | January 21 – March 13 | 6 weeks before |
| Spinach | Direct sow | January 21 – March 13 | 6 weeks before |
| Sweet Potato | Start indoors | January 21 – March 13 | 6 weeks before |
| Tomatoes | Start indoors | January 21 – March 13 | 6 weeks before |
| Bok Choy | Start indoors | January 28 – March 20 | 5 weeks before |
| Kohlrabi | Start indoors | January 28 – March 20 | 5 weeks before |
| Swiss Chard | Start indoors | January 28 – March 20 | 5 weeks before |
| Arugula | Direct sow | February 4 – March 27 | 4 weeks before |
| Baby Salad Greens | Direct sow | February 4 – March 27 | 4 weeks before |
| Beets | Direct sow | February 4 – March 27 | 4 weeks before |
| Green Onions | Direct sow | February 4 – March 27 | 4 weeks before |
| Mustard Greens | Direct sow | February 4 – March 27 | 4 weeks before |
| Okra | Start indoors | February 4 – March 27 | 4 weeks before |
| Radishes | Direct sow | February 4 – March 27 | 4 weeks before |
| Turnips | Direct sow | February 4 – March 27 | 4 weeks before |
| Cabbage | Set out | February 11 – April 3 | 3 weeks before |
| Carrots | Direct sow | February 11 – April 3 | 3 weeks before |
| Collards | Direct sow | February 11 – April 3 | 3 weeks before |
| Collards | Set out | February 11 – April 3 | 3 weeks before |
| Cucumbers | Start indoors | February 11 – April 3 | 3 weeks before |
| Green Onions | Set out | February 11 – April 3 | 3 weeks before |
| Kale | Direct sow | February 11 – April 3 | 3 weeks before |
| Kale | Set out | February 11 – April 3 | 3 weeks before |
| Kohlrabi | Direct sow | February 11 – April 3 | 3 weeks before |
| Kohlrabi | Set out | February 11 – April 3 | 3 weeks before |
| Leaf Lettuce | Direct sow | February 11 – April 3 | 3 weeks before |
| Pumpkins | Start indoors | February 11 – April 3 | 3 weeks before |
| Summer Squash | Start indoors | February 11 – April 3 | 3 weeks before |
| Winter Squash | Start indoors | February 11 – April 3 | 3 weeks before |
| Zucchini | Start indoors | February 11 – April 3 | 3 weeks before |
| Bok Choy | Direct sow | February 18 – April 10 | 2 weeks before |
| Bok Choy | Set out | February 18 – April 10 | 2 weeks before |
| Broccoli | Set out | February 18 – April 10 | 2 weeks before |
| Cilantro | Direct sow | February 18 – April 10 | 2 weeks before |
| Leaf Lettuce | Set out | February 18 – April 10 | 2 weeks before |
| Swiss Chard | Direct sow | February 18 – April 10 | 2 weeks before |
| Swiss Chard | Set out | February 18 – April 10 | 2 weeks before |
| Dill | Direct sow | February 25 – April 17 | 1 week before |
| Bush Beans | Direct sow | March 11 – May 1 | 1 week after |
| Cucumbers | Set out | March 11 – May 1 | 1 week after |
| Pumpkins | Direct sow | March 11 – May 1 | 1 week after |
| Pumpkins | Set out | March 11 – May 1 | 1 week after |
| Summer Squash | Direct sow | March 11 – May 1 | 1 week after |
| Summer Squash | Set out | March 11 – May 1 | 1 week after |
| Sweet Corn | Direct sow | March 11 – May 1 | 1 week after |
| Tomatoes | Set out | March 11 – May 1 | 1 week after |
| Winter Squash | Direct sow | March 11 – May 1 | 1 week after |
| Winter Squash | Set out | March 11 – May 1 | 1 week after |
| Zucchini | Direct sow | March 11 – May 1 | 1 week after |
| Zucchini | Set out | March 11 – May 1 | 1 week after |
| Cucumbers | Direct sow | March 18 – May 8 | 2 weeks after |
| Okra | Direct sow | March 18 – May 8 | 2 weeks after |
| Okra | Set out | March 18 – May 8 | 2 weeks after |
| Peppers | Set out | March 18 – May 8 | 2 weeks after |
| Southern Peas | Direct sow | March 18 – May 8 | 2 weeks after |
| Sweet Potato | Set out | March 18 – May 8 | 2 weeks after |
The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.
What survives the winter changes across Sierra Vista-Douglas, AZ
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 57 come through the winter in zone 8a and only 54 in zone 8b. That is a different garden at each end of the same metro.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 8a | 5 | 57 of 74 | 8 |
| 8b | 16 | 54 of 74 | 11 |
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.
Cautious — shortens the seasonMedian across stationsOptimistic
- Last spring freeze
- Plan to May 9 to be careful. Median March 4 – April 24 across 13 stations; February 3 is the optimistic end.
- First fall freeze
- Plan to October 14 to be careful. Median October 27 – November 29 across 13 stations; December 17 is the optimistic end.
NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.
The 13 stations behind these numbers
All 13 NOAA stations whose normals this page quotes, spanning about 109 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole metro area.
A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.
Every figure above comes from these, and each is named so you can check it. Which station serves a given ZIP code, and how far away it is, varies across the metro — the table below gives it per ZIP code rather than this page averaging it.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Benson 6Se, AZ | USC00020683 | April 12 | November 1 | 202 days |
| Bisbee 1Wnw, AZ | USC00020775 | April 1 | November 10 | 222 days |
| Bowie, AZ | USC00020958 | April 1 | November 6 | 217 days |
| Cascabel, AZ | USC00021330 | April 24 | October 31 | 187 days |
| Coronado Nmem, AZ | USC00022140 | April 7 | November 9 | 213 days |
| Douglas Bisbee Inl AP, AZ | USW00093026 | April 11 | November 2 | 203 days |
| Douglas, AZ | USC00022659 | March 18 | November 13 | 235 days |
| Ft Huachuca Pioneer Airfield, AZ | USW00053146 | March 16 | November 21 | 246 days |
| Mc Neal, AZ | USC00025418 | April 6 | November 10 | 215 days |
| Paradise, AZ | USC00026242 | April 21 | October 27 | 188 days |
| Pearce - Sunsites, AZ | USC00026353 | April 14 | November 2 | 200 days |
| Sierra Vista, AZ | USC00027880 | April 5 | November 9 | 216 days |
| Tombstone, AZ | USC00028619 | March 4 | November 29 | 264 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Every ZIP code in Sierra Vista-Douglas, AZ
Zones are published per ZIP code, not per metro area, so this is the exact answer rather than the metro area's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.
| ZIP code | USDA zone | Nearest NOAA station | Distance |
|---|---|---|---|
| 85602 | 8b | Cascabel, AZ | 12.1 km |
| 85603 | 8b | Bisbee 1Wnw, AZ | 1.9 km |
| 85605 | 8b | Bowie, AZ | 2.7 km |
| 85606 | 8b | Pearce - Sunsites, AZ | 11.7 km |
| 85607 | 8a | Douglas, AZ | 25.1 km |
| 85608 | 8a | Douglas Bisbee Inl AP, AZ | 2.4 km |
| 85609 | 8b | Benson 6Se, AZ | 25.0 km |
| 85610 | 8b | Mc Neal, AZ | 15.5 km |
| 85613 | 8b | Ft Huachuca Pioneer Airfield, AZ | 8.0 km |
| 85615 | 8b | Coronado Nmem, AZ | 7.2 km |
| 85616 | 8b | Ft Huachuca Pioneer Airfield, AZ | 14.5 km |
| 85617 | 8b | Mc Neal, AZ | 5.5 km |
| 85620 | 8b | Bisbee 1Wnw, AZ | 12.2 km |
| 85625 | 8a | Pearce - Sunsites, AZ | 17.7 km |
| 85626 | 8a | Douglas, AZ | 3.2 km |
| 85627 | 8b | Benson 6Se, AZ | 14.1 km |
| 85630 | 8b | Benson 6Se, AZ | 5.8 km |
| 85632 | 8a | Paradise, AZ | 14.1 km |
| 85635 | 8b | Sierra Vista, AZ | 10.6 km |
| 85638 | 8b | Tombstone, AZ | 5.2 km |
| 85650 | 8b | Sierra Vista, AZ | 8.6 km |
ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.
Your own ZIP
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.
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What survives my winter?
Runs on the hardiness zone, so it answers for all of Sierra Vista-Douglas, AZ at once — zone across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Other places to compare
These metros span exactly the same zones — 8a–8b — so the same plants are in and out of range across them. The freeze dates and the spring calendar are their own.
- Fayetteville, NC — zones 8a–8b
- Texarkana, TX-AR — zones 8a–8b
- Athens-Clarke County, GA — zones 8a–8b
- Auburn-Opelika, AL — zones 8a–8b
- Medford, OR — zones 8a–8b
- Olympia-Lacey-Tumwater, WA — zones 8a–8b
- Jacksonville, NC — zones 8a–8b
- Greenville, NC — zones 8a–8b
Gardening in Arizona — zones 5b– 10a covers the whole state: how its 415 ZIP codes divide between 10 hardiness zones, and the freeze dates across every NOAA station in it.
Other metro areas in AZ:
- Yuma, AZ Zones 9a–10a
- Phoenix-Mesa-Chandler, AZ Zones 9a–10a
- Tucson, AZ Zones 8b–9b
- Prescott Valley-Prescott, AZ Zones 7a–9b
- Flagstaff, AZ Zones 5b–7b
- Lake Havasu City-Kingman, AZ Zones 7b–10a
Gear
If you want to act on this
Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.
- Shade clothSummer highs here average 94 °F, at or above the 90 °F point where lettuce and spinach bolt and tomato pollen fails.
- Row cover and frost clothThe season here closes at the first fall freeze dated above — a cover buys back some of those days at the end.
- MulchFor the perennials nearest their cold limit in zone 8a, where an insulated crown is what decides whether they come back.
As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.
Sources
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.