USDA Hardiness Zone 8b
Frost Dates for 85616 — Huachuca City, Arizona
NOAA 1991–2020 normals from Fort Huachuca Pioneer Airfield, AZ (4,768 ft), 7 miles southwest.
Updated
In Huachuca City, the last spring frost (32°F) is around March 16 in half of years and has passed by April 12 in nine years out of ten. The first fall frost comes around November 21, as early as November 3 one year in ten, leaving a typical freeze-free season of 246 days (NOAA, Fort Huachuca Pioneer Airfield, AZ).
- Last spring frost
- March 16
- First fall frost
- November 21
- Growing season
- 246 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 17%
- Snow per year
- 0.4"
median, 1991–2020
median, 1991–2020
3 of 18 observed
NOAA normal
Frost risk by date in Huachuca City
Half of springs at Fort Huachuca Pioneer Airfield, AZ see their last 32°F night by March 16; only one in ten is past it by February 19, and one in ten still has one after April 12. Planting tender crops after March 31 leaves a 30% risk of a frost on them, after April 6 20%, and after April 12 10%. The 27 days between the even-odds date and the one-in-ten date is wider than at 71% of the 98 Arizona stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by November 21 in half of years, as early as November 3 one year in ten, and holds off past December 7 one year in ten. A hard freeze of 28°F follows 15 days later, around December 6; in spring the one-in-ten date for 28°F is March 23, 20 days before the 32°F one. The freeze-free season lasts 246 days in a typical year, longer than at 54% of the 98 Arizona stations; it reaches 277 days one year in ten and falls short of 214 one year in ten. On average 34 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 24 days longer, to about April 9, and return around November 8. Nights of 24°F, cold enough to damage hardier plants, come in 89% of winters and 16°F in 11%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 20 | Mar 27 | Apr 1 | Apr 6 | Apr 9 | Apr 12 | Apr 17 | Apr 22 | Apr 26 |
| 32°F | Feb 19 | Mar 1 | Mar 7 | Mar 12 | Mar 16 | Mar 23 | Mar 31 | Apr 6 | Apr 12 |
| 28°F | Jan 16 | Jan 30 | Feb 7 | Feb 13 | Feb 20 | Feb 27 | Mar 3 | Mar 9 | Mar 23 |
| 24°F89% of yrs | Dec 23 | Jan 3 | Jan 9 | Jan 16 | Jan 26 | Feb 1 | Feb 8 | Feb 14 | Feb 23 |
| 20°F46% of yrs | too rare for a date | ||||||||
| 16°F11% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 24 | Oct 29 | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 16 | Nov 19 | Nov 24 |
| 32°F | Nov 3 | Nov 8 | Nov 14 | Nov 18 | Nov 21 | Nov 24 | Nov 29 | Dec 3 | Dec 7 |
| 28°F | Nov 18 | Nov 25 | Nov 29 | Dec 3 | Dec 6 | Dec 9 | Dec 13 | Dec 17 | Dec 24 |
| 24°F89% of yrs | Dec 1 | Dec 7 | Dec 11 | Dec 16 | Dec 22 | Dec 26 | Jan 1 | Jan 10 | Jan 25 |
| 20°F46% of yrs | too rare for a date | ||||||||
| 16°F11% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Fort Huachuca Pioneer Airfield, AZ, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 85616 →Compare Huachuca City with another place →
Compared with the next station
The nearest other station, Sierra Vista, AZ, 11 miles south of Huachuca City and 162 feet lower, has a last frost 20 days later (April 5), a first frost 12 days earlier (November 9), a season 30 days shorter.
When it snows in Huachuca City, Arizona
Measurable snow is rare here: only 3 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Sierra Vista, AZ, 10.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 85616
| When | What to do |
|---|---|
| January 5 – January 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 19 – February 2 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 16 – March 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 29 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 7 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 21 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 85616 is 7 miles from Fort Huachuca Pioneer Airfield, AZ, which stands at 4,768 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85616 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.