USDA Hardiness Zone 9b
Frost Dates for 85356 — Wellton, Arizona
NOAA 1991–2020 normals from Yuma 27 ENE, AZ (620 ft), 11 miles north.
Updated
A freeze (32°F) reaches Wellton in 76% of winters. When it does, the first fall frost comes around December 21 and the last spring frost around January 11; after February 14 the chance of another is under 8%.
- Last spring frost
- January 11
- First fall frost
- December 21
- Winters with a freeze
- 76%
- Hardiness zone
- 9b
50%, in freezing years
50%, in freezing years
32°F or below, 1991–2020
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 24 observed
NOAA normal
Frost risk by date in Wellton
In the 76% of winters that bring a 32°F night, half of springs at Yuma 27 ENE, AZ see their last 32°F night by January 11; only one in ten is past it by December 17, and one in ten still has one after February 14. Counting the winters with no freeze at all, the risk of a 32°F night after February 14 is under 8% and after January 11 38%. The 34 days between the even-odds date and the one-in-ten date is wider than at 91% 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 21 in half of years, as early as December 1 one year in ten, and holds off past January 25 one year in ten. A hard freeze of 28°F is less common: it came in 26% of winters. The freeze-free season lasts 347 days in a typical year, longer than at 92% of the 98 Arizona stations; it reaches 365 days one year in ten and falls short of 310 one year in ten. On average 5 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 27 days longer, to about February 7, and return around December 8. A 24°F night is unusual: 2% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F99% of yrs | Jan 6 | Jan 14 | Jan 22 | Jan 31 | Feb 7 | Feb 13 | Feb 20 | Feb 27 | Mar 3 |
| 32°F76% of yrs | Dec 17 | Dec 26 | Dec 31 | Jan 4 | Jan 11 | Jan 21 | Jan 31 | Feb 6 | Feb 14 |
| 28°F26% of yrs | too rare for a date | ||||||||
| 24°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F99% of yrs | Nov 22 | Nov 28 | Dec 1 | Dec 5 | Dec 8 | Dec 12 | Dec 15 | Dec 19 | Dec 26 |
| 32°F76% of yrs | Dec 1 | Dec 9 | Dec 13 | Dec 17 | Dec 21 | Dec 25 | Dec 31 | Jan 7 | Jan 25 |
| 28°F26% of yrs | too rare for a date | ||||||||
| 24°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Yuma 27 ENE, 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 85356 →Compare Wellton with another place →
Weather by month in Wellton
July is the warmest month at Yuma 27 ENE, AZ, averaging 106°F by day and 80°F at night; December is the coldest at 67°F and 42°F. From March to November the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 22% of years.
Warmth for growing adds up to 8,521 growing degree days a year (base 50°F), more than at 86% of the 102 Arizona stations. 41% of them (3,467) have built up by the end of June, and July adds the most, 1,333. Precipitation totals 4.0 inches a year, most in January (0.6") and least in May (0.0"); May to September bring 32% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 68 | 43 | 0.6 | 38% | 2 | 194 |
| Feb | 72 | 45 | 0.6 | 22% | 1 | 249 |
| Mar | 79 | 51 | 0.4 | 1% | 0 | 454 |
| Apr | 85 | 56 | 0.1 | 0% | 0 | 617 |
| May | 93 | 62 | 0.0 | 0% | 0 | 859 |
| Jun | 103 | 71 | 0.0 | 0% | 0 | 1095 |
| Jul | 106 | 80 | 0.3 | 0% | 0 | 1333 |
| Aug | 105 | 80 | 0.6 | 0% | 0 | 1317 |
| Sep | 100 | 73 | 0.4 | 0% | 0 | 1092 |
| Oct | 90 | 60 | 0.2 | 0% | 0 | 766 |
| Nov | 77 | 49 | 0.4 | 7% | <1 | 392 |
| Dec | 67 | 42 | 0.4 | 52% | 2 | 154 |
Monthly normals 1991–2020 at Yuma 27 ENE, AZ (620 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, Yuma Mcas, AZ, 28 miles west of Wellton and 407 feet lower, has a 32°F night in 8% of winters against 76% here, and a coolest-month low 5°F warmer (47°F).
When it snows in Wellton, Arizona
Measurable snow is rare here: only 0 of 24 winters from 1991 to 2020 recorded 0.1 inch or more at Tacna 3 NE, AZ, 13 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 85356 is 11 miles from Yuma 27 ENE, AZ, which stands at 620 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85356 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.