USDA Hardiness Zone 8a
Frost Dates for 86335 — Rimrock, Arizona
NOAA 1991–2020 normals from Montezuma Castle Nm, AZ (3,180 ft), 6 miles southwest.
Updated
In Rimrock, the last spring frost (32°F) is around April 16 in half of years and has passed by May 2 in nine years out of ten. The first fall frost comes around October 30, as early as October 15 one year in ten, leaving a typical freeze-free season of 196 days (NOAA, Montezuma Castle Nm, AZ).
- Last spring frost
- April 16
- First fall frost
- October 30
- Growing season
- 196 days
- Hardiness zone
- 8a
50% probability
50% probability
freeze-free, 50%
10 to 15°F (-12.2 to -9.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 26 observed
NOAA normal
Frost risk by date in Rimrock
Half of springs at Montezuma Castle Nm, AZ see their last 32°F night by April 16; only one in ten is past it by March 28, and one in ten still has one after May 2. Planting tender crops after April 24 leaves a 30% risk of a frost on them, after April 28 20%, and after May 2 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 98 Arizona stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 30 in half of years, as early as October 15 one year in ten, and holds off past November 13 one year in ten. A hard freeze of 28°F follows 11 days later, around November 10; in spring the one-in-ten date for 28°F is April 15, 17 days before the 32°F one. The freeze-free season lasts 196 days in a typical year, shorter than at 69% of the 98 Arizona stations; it reaches 221 days one year in ten and falls short of 173 one year in ten. On average 99 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 15 days longer, to about May 1, and return around October 19. Severe cold of 16°F or below comes in 90% of winters, usually between December 17 and January 18.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 18 | Apr 22 | Apr 26 | Apr 29 | May 1 | May 3 | May 6 | May 11 | May 16 |
| 32°F | Mar 28 | Apr 4 | Apr 8 | Apr 12 | Apr 16 | Apr 20 | Apr 24 | Apr 28 | May 2 |
| 28°F | Mar 2 | Mar 7 | Mar 11 | Mar 16 | Mar 21 | Mar 28 | Apr 2 | Apr 8 | Apr 15 |
| 24°F | Feb 6 | Feb 14 | Feb 21 | Feb 25 | Feb 28 | Mar 2 | Mar 6 | Mar 9 | Mar 17 |
| 20°F | Jan 9 | Jan 22 | Jan 30 | Feb 4 | Feb 10 | Feb 14 | Feb 19 | Feb 24 | Mar 1 |
| 16°F90% of yrs | Dec 20 | Dec 31 | Jan 4 | Jan 9 | Jan 18 | Jan 28 | Feb 3 | Feb 10 | Feb 20 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 4 | Oct 9 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 | Nov 2 |
| 32°F | Oct 15 | Oct 21 | Oct 24 | Oct 28 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 13 |
| 28°F | Oct 25 | Oct 30 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 23 |
| 24°F | Nov 5 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 23 | Nov 26 | Dec 1 | Dec 5 |
| 20°F | Nov 16 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 23 |
| 16°F90% of yrs | Nov 27 | Dec 1 | Dec 6 | Dec 10 | Dec 17 | Dec 24 | Dec 29 | Jan 4 | Jan 18 |
Freeze probabilities 1991–2020 at Montezuma Castle Nm, 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 86335 →Compare Rimrock with another place →
Weather by month in Rimrock
July is the warmest month at Montezuma Castle Nm, AZ, averaging 101°F by day and 64°F at night; December is the coldest at 59°F and 25°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 84% of years and May still brings one in 13% of years.
Warmth for growing adds up to 4,958 growing degree days a year (base 50°F), fewer than at 62% of the 102 Arizona stations. 36% of them (1,801) have built up by the end of June, and July adds the most, 1,004. Precipitation totals 13.3 inches a year, most in August (2.1") and least in June (0.2"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 61 | 26 | 1.4 | 100% | 26 | 5 |
| Feb | 65 | 29 | 1.3 | 100% | 19 | 30 |
| Mar | 72 | 35 | 1.2 | 99% | 8 | 144 |
| Apr | 79 | 40 | 0.5 | 84% | 2 | 294 |
| May | 88 | 47 | 0.4 | 13% | <1 | 542 |
| Jun | 98 | 54 | 0.2 | 0% | 0 | 788 |
| Jul | 101 | 64 | 1.5 | 0% | 0 | 1004 |
| Aug | 99 | 63 | 2.1 | 0% | 0 | 950 |
| Sep | 93 | 55 | 1.5 | 0% | 0 | 720 |
| Oct | 82 | 43 | 1.0 | 53% | 2 | 391 |
| Nov | 69 | 32 | 0.7 | 100% | 16 | 88 |
| Dec | 59 | 25 | 1.5 | 100% | 26 | 4 |
Monthly normals 1991–2020 at Montezuma Castle Nm, AZ (3,180 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Sedona, AZ, 17 miles north of Rimrock and 1,040 feet higher, has a last frost 15 days earlier (April 1), a first frost 18 days later (November 17), a season 33 days longer.
When it snows in Rimrock, Arizona
Measurable snow is rare here: only 0 of 26 winters from 1991 to 2020 recorded 0.1 inch or more at Montezuma Castle Nm, AZ, 5.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 86335
| When | What to do |
|---|---|
| February 5 – February 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 19 – March 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 19 – April 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 30 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 86335 is 6 miles from Montezuma Castle Nm, AZ, which stands at 3,180 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 86322 (Camp Verde). The 2023 USDA Plant Hardiness Zone Map lists ZIP 86335 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°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.