USDA Hardiness Zone 9b
Frost Dates for 85132 — Florence, Arizona
NOAA 1991–2020 normals from Florence, AZ (1,400 ft), 11 miles northwest.
Updated
In Florence, the last spring frost (32°F) is around January 30 in half of years and has passed by February 24 in nine years out of ten. The first fall frost comes around December 12, as early as November 22 one year in ten, leaving a typical freeze-free season of 319 days (NOAA, Florence, AZ).
- Last spring frost
- January 30
- First fall frost
- December 12
- Growing season
- 319 days
- Hardiness zone
- 9b
50% probability
50% probability
freeze-free, 50%
25 to 30°F (-3.9 to -1.1°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 17 observed
NOAA normal
Frost risk by date in Florence
Half of springs at Florence, AZ see their last 32°F night by January 30; only one in ten is past it by December 27, and one in ten still has one after February 24. Planting tender crops after February 10 leaves a 30% risk of a frost on them, after February 17 20%, and after February 24 10%. The 25 days between the even-odds date and the one-in-ten date is wider than at 63% 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 December 12 in half of years, as early as November 22 one year in ten, and holds off past January 12 one year in ten. A hard freeze of 28°F follows 14 days later, around December 26; in spring the one-in-ten date for 28°F is February 11, 13 days before the 32°F one. The freeze-free season lasts 319 days in a typical year, longer than at 82% of the 98 Arizona stations; it reaches 354 days one year in ten and falls short of 286 one year in ten. On average 10 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 22 days longer, to about February 21, and return around November 29. A 24°F night is unusual: 16% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 25 | Feb 3 | Feb 11 | Feb 17 | Feb 21 | Feb 26 | Mar 1 | Mar 6 | Mar 13 |
| 32°F95% of yrs | Dec 27 | Jan 4 | Jan 10 | Jan 20 | Jan 30 | Feb 4 | Feb 10 | Feb 17 | Feb 24 |
| 28°F57% of yrs | Dec 11 | Dec 19 | Dec 29 | Jan 2 | Jan 8 | Jan 14 | Jan 22 | Feb 2 | Feb 11 |
| 24°F16% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 12 | Nov 18 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 19 |
| 32°F95% of yrs | Nov 22 | Nov 29 | Dec 4 | Dec 7 | Dec 12 | Dec 16 | Dec 23 | Jan 1 | Jan 12 |
| 28°F57% of yrs | Dec 1 | Dec 8 | Dec 13 | Dec 19 | Dec 26 | Dec 31 | Jan 6 | Jan 16 | Jan 31 |
| 24°F16% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Florence, 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 85132 →Compare Florence with another place →
Weather by month in Florence
July is the warmest month at Florence, AZ, averaging 105°F by day and 78°F at night; December is the coldest at 67°F and 41°F. From March to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 42% of years.
Warmth for growing adds up to 8,251 growing degree days a year (base 50°F), more than at 83% of the 102 Arizona stations. 41% of them (3,353) have built up by the end of June, and July adds the most, 1,289. Precipitation totals 8.8 inches a year, most in January (1.4") and least in June (0.0"); May to September bring 34% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 68 | 42 | 1.4 | 68% | 3 | 172 |
| Feb | 71 | 44 | 0.9 | 42% | 1 | 212 |
| Mar | 79 | 49 | 1.2 | 5% | 1 | 428 |
| Apr | 86 | 53 | 0.3 | 0% | 0 | 588 |
| May | 94 | 61 | 0.4 | 0% | 0 | 853 |
| Jun | 103 | 70 | 0.0 | 0% | 0 | 1101 |
| Jul | 105 | 78 | 1.2 | 0% | 0 | 1289 |
| Aug | 103 | 78 | 1.1 | 0% | 0 | 1254 |
| Sep | 99 | 72 | 0.3 | 0% | 0 | 1063 |
| Oct | 89 | 60 | 0.5 | 0% | 0 | 753 |
| Nov | 77 | 48 | 0.5 | 21% | 1 | 386 |
| Dec | 67 | 41 | 1.0 | 71% | 4 | 152 |
Monthly normals 1991–2020 at Florence, AZ (1,400 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, Casa Grande Nm, AZ, 18 miles west of Florence, has a last frost 18 days later (February 17), a first frost 13 days earlier (November 29), a season 35 days shorter.
When it snows in Florence, Arizona
Measurable snow is rare here: only 0 of 17 winters from 1991 to 2020 recorded 0.1 inch or more at Florence, AZ, 10.9 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 85132
| When | What to do |
|---|---|
| November 21 – December 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 5 – December 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 2 – January 16 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| January 30 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 19 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 28 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 12 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 85132 is 11 miles from Florence, AZ, which stands at 1,400 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85132 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°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.