USDA Hardiness Zone 8b
Frost Dates for 85736 — Tucson, Arizona
NOAA 1991–2020 normals from Anvil Rch, AZ (2,759 ft), 5 miles west.
Updated
In Tucson, the last spring frost (32°F) is around March 27 in half of years and has passed by April 18 in nine years out of ten. The first fall frost comes around November 9, as early as October 25 one year in ten, leaving a typical freeze-free season of 226 days (NOAA, Anvil Rch, AZ).
- Last spring frost
- March 27
- First fall frost
- November 9
- Growing season
- 226 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
- 0%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
0 of 19 observed
NOAA normal
Frost risk by date in Tucson
Half of springs at Anvil Rch, AZ see their last 32°F night by March 27; only one in ten is past it by March 5, and one in ten still has one after April 18. Planting tender crops after April 5 leaves a 30% risk of a frost on them, after April 10 20%, and after April 18 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 54% 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 9 in half of years, as early as October 25 one year in ten, and holds off past November 26 one year in ten. A hard freeze of 28°F follows 12 days later, around November 21; in spring the one-in-ten date for 28°F is April 2, 16 days before the 32°F one. The freeze-free season lasts 226 days in a typical year, shorter than at 52% of the 98 Arizona stations; it reaches 255 days one year in ten and falls short of 197 one year in ten. On average 54 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 17 days longer, to about April 13, and return around November 1. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 37%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 27 | Apr 2 | Apr 6 | Apr 10 | Apr 13 | Apr 18 | Apr 21 | Apr 25 | Apr 30 |
| 32°F | Mar 5 | Mar 12 | Mar 17 | Mar 22 | Mar 27 | Mar 31 | Apr 5 | Apr 10 | Apr 18 |
| 28°F | Feb 9 | Feb 19 | Feb 26 | Mar 3 | Mar 6 | Mar 10 | Mar 16 | Mar 23 | Apr 2 |
| 24°F | Jan 7 | Jan 23 | Jan 31 | Feb 6 | Feb 13 | Feb 20 | Feb 27 | Mar 4 | Mar 10 |
| 20°F82% of yrs | Dec 14 | Dec 29 | Jan 5 | Jan 12 | Jan 22 | Jan 30 | Feb 4 | Feb 12 | Feb 25 |
| 16°F37% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 16 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 11 | Nov 15 |
| 32°F | Oct 25 | Oct 30 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 16 | Nov 19 | Nov 26 |
| 28°F | Nov 2 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 3 | Dec 9 |
| 24°F | Nov 14 | Nov 20 | Nov 24 | Nov 29 | Dec 3 | Dec 7 | Dec 12 | Dec 19 | Jan 1 |
| 20°F82% of yrs | Nov 24 | Dec 1 | Dec 6 | Dec 12 | Dec 18 | Dec 27 | Jan 2 | Jan 10 | Jan 29 |
| 16°F37% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Anvil Rch, 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 85736 →Compare Tucson with another place →
Weather by month in Tucson
July is the warmest month at Anvil Rch, AZ, averaging 99°F by day and 70°F at night; December is the coldest at 65°F and 33°F. A freezing night is all but certain in every month from November to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 89% of years and April still brings one in 39% of years.
Warmth for growing adds up to 6,217 growing degree days a year (base 50°F), more than at 54% of the 102 Arizona stations. 39% of them (2,441) have built up by the end of June, and July adds the most, 1,063.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 66 | 34 | 100% | 15 | 71 |
| Feb | 69 | 36 | 99% | 10 | 106 |
| Mar | 75 | 40 | 89% | 5 | 249 |
| Apr | 82 | 45 | 39% | 1 | 408 |
| May | 90 | 53 | 0% | 0 | 670 |
| Jun | 99 | 63 | 0% | 0 | 937 |
| Jul | 99 | 70 | 0% | 0 | 1063 |
| Aug | 96 | 69 | 0% | 0 | 1015 |
| Sep | 94 | 63 | 0% | 0 | 843 |
| Oct | 85 | 51 | 24% | 1 | 556 |
| Nov | 74 | 39 | 91% | 6 | 231 |
| Dec | 65 | 33 | 100% | 15 | 68 |
Monthly normals 1991–2020 at Anvil Rch, AZ (2,759 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, Kitt Peak, AZ, 18 miles west of Tucson and 4,031 feet higher, has a last frost 30 days later (April 26), a first frost 5 days earlier (November 4), a season 31 days shorter.
When it snows in Tucson, Arizona
Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Anvil Rch, AZ, 5.3 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 85736
| When | What to do |
|---|---|
| January 16 – January 30 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 30 – February 13 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 27 – March 13 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 27 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 17 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 9 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 85736 is 5 miles from Anvil Rch, AZ, which stands at 2,759 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85736 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.