USDA Hardiness Zone 7a
Frost Dates for 86043 — Second Mesa, Arizona
NOAA 1991–2020 normals from Keams Canyon, AZ (6,205 ft), 17 miles east.
Updated
In Second Mesa, the last spring frost (32°F) is around May 16 in half of years and has passed by June 5 in nine years out of ten. The first fall frost comes around October 10, as early as September 29 one year in ten, leaving a typical freeze-free season of 147 days (NOAA, Keams Canyon, AZ).
- Last spring frost
- May 16
- First fall frost
- October 10
- Growing season
- 147 days
- Hardiness zone
- 7a
50% probability
50% probability
freeze-free, 50%
0 to 5°F (-17.8 to -15.0°C) coldest night
- First snow
- December 8
- Last snow
- March 23
- Winters with snow
- 88%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
14 of 16 observed
NOAA normal
Frost risk by date in Second Mesa
Half of springs at Keams Canyon, AZ see their last 32°F night by May 16; only one in ten is past it by April 29, and one in ten still has one after June 5. Planting tender crops after May 25 leaves a 30% risk of a frost on them, after May 31 20%, and after June 5 10%. The 20 days between the even-odds date and the one-in-ten date is narrower than at 52% of the 98 Arizona stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 10 in half of years, as early as September 29 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 10 days later, around October 20; in spring the one-in-ten date for 28°F is May 20, 16 days before the 32°F one. The freeze-free season lasts 147 days in a typical year, shorter than at 90% of the 98 Arizona stations; it reaches 169 days one year in ten and falls short of 123 one year in ten. On average 172 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 16 days longer, to about June 1, and return around October 2. Severe cold of 16°F or below comes every winter, usually between November 19 and March 7.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 14 | May 19 | May 24 | May 29 | Jun 1 | Jun 3 | Jun 6 | Jun 9 | Jun 15 |
| 32°F | Apr 29 | May 3 | May 8 | May 12 | May 16 | May 19 | May 25 | May 31 | Jun 5 |
| 28°F | Apr 14 | Apr 20 | Apr 24 | Apr 28 | May 1 | May 4 | May 9 | May 13 | May 20 |
| 24°F | Mar 28 | Apr 4 | Apr 8 | Apr 12 | Apr 17 | Apr 21 | Apr 26 | May 1 | May 8 |
| 20°F | Mar 6 | Mar 13 | Mar 18 | Mar 23 | Mar 29 | Apr 3 | Apr 8 | Apr 14 | Apr 24 |
| 16°F | Feb 13 | Feb 23 | Feb 28 | Mar 4 | Mar 7 | Mar 11 | Mar 15 | Mar 21 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 15 |
| 32°F | Sep 29 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 24 |
| 28°F | Oct 6 | Oct 11 | Oct 15 | Oct 17 | Oct 20 | Oct 24 | Oct 28 | Nov 1 | Nov 5 |
| 24°F | Oct 15 | Oct 20 | Oct 25 | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 10 | Nov 14 |
| 20°F | Oct 24 | Oct 31 | Nov 3 | Nov 7 | Nov 11 | Nov 13 | Nov 17 | Nov 19 | Nov 24 |
| 16°F | Nov 2 | Nov 10 | Nov 14 | Nov 17 | Nov 19 | Nov 22 | Nov 25 | Nov 28 | Dec 3 |
Freeze probabilities 1991–2020 at Keams Canyon, 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 86043 →Compare Second Mesa with another place →
Weather by month in Second Mesa
July is the warmest month at Keams Canyon, AZ, averaging 89°F by day and 57°F at night; December is the coldest at 44°F and 17°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 82% of years and June still brings one in 18% of years.
Warmth for growing adds up to 2,647 growing degree days a year (base 50°F), fewer than at 92% of the 102 Arizona stations. 30% of them (789) have built up by the end of June, and July adds the most, 714.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 45 | 18 | 100% | 30 | 0 |
| Feb | 49 | 22 | 100% | 27 | 0 |
| Mar | 58 | 27 | 100% | 27 | 8 |
| Apr | 66 | 32 | 100% | 15 | 63 |
| May | 75 | 39 | 82% | 6 | 231 |
| Jun | 86 | 47 | 18% | <1 | 486 |
| Jul | 89 | 57 | 0% | 0 | 714 |
| Aug | 86 | 55 | 0% | 0 | 632 |
| Sep | 79 | 47 | 12% | <1 | 397 |
| Oct | 68 | 35 | 97% | 10 | 107 |
| Nov | 56 | 25 | 100% | 26 | 8 |
| Dec | 44 | 17 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Keams Canyon, AZ (6,205 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
When it snows in Second Mesa, Arizona
The first measurable snow (0.1 inch or more) in Second Mesa usually arrives around December 8, and the last of the season around March 23. Those are the middle dates across the winters of 1991–2020 at Keams Canyon, AZ, 17.4 miles away: half of years saw snow earlier, half later. Snow fell in 88% of those winters. The last 32°F night of spring typically comes 54 days after the last snow.
Planting calendar for 86043
| When | What to do |
|---|---|
| March 7 – March 21 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 21 – April 4 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 18 – May 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 18 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 10 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 86043 is 17 miles from Keams Canyon, AZ, which stands at 6,205 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 86510 (Pinon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 86043 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°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.