USDA Hardiness Zone 10a
Frost Dates for 85350 — Somerton, Arizona
NOAA 1991–2020 normals from Yuma Mcas, AZ (213 ft), 7 miles northeast.
Updated
Frost is not a yearly event in Somerton: a night at or below 32°F came in 8% of the winters of 1991–2020 at Yuma Mcas, AZ, and a 36°F night, cold enough for frost on exposed leaves, in 51%. There is no reliable "last frost date" here; most years have none.
- Winters with a freeze
- 8%
- Winters with 36°F
- 51%
- Coldest month low
- 47°F
- Hardiness zone
- 10a
32°F or below, 1991–2020
frost possible on leaves
average, December
30 to 35°F (-1.1 to 1.7°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 20 observed
NOAA normal
Frost risk by date in Somerton
At Yuma Mcas, AZ, 7 miles northeast of Somerton, 8% of the winters of 1991–2020 had at least one night at or below 32°F, 1% reached 28°F. Nights of 36°F, enough for frost on exposed leaves, are more common (51% of winters) and, when they come, fall between about December 30 and January 6. January is the month most likely to bring one: a 6% chance in a given year. 3 of the 102 other Arizona stations behind this site's ZIP pages freeze in fewer than half of winters too.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F51% of yrs | Dec 14 | Dec 23 | Dec 29 | Jan 2 | Jan 6 | Jan 12 | Jan 16 | Jan 26 | Feb 6 |
| 32°F8% of yrs | too rare for a date | ||||||||
| 28°F1% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F51% of yrs | Dec 11 | Dec 15 | Dec 22 | Dec 26 | Dec 30 | Jan 1 | Jan 7 | Jan 15 | Jan 28 |
| 32°F8% of yrs | too rare for a date | ||||||||
| 28°F1% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Yuma Mcas, 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 85350 →Compare Somerton with another place →
Weather by month in Somerton
August is the warmest month at Yuma Mcas, AZ, averaging 106°F by day and 83°F at night; December is the coldest at 68°F and 47°F. Every month stays under a 10% chance of a 32°F night; January is the likeliest at 6%.
Warmth for growing adds up to 9,509 growing degree days a year (base 50°F), more than at 99% of the 102 Arizona stations. 42% of them (3,973) have built up by the end of June, and August adds the most, 1,389. Precipitation totals 3.2 inches a year, most in September (0.7") and least in June (0.0"); May to September bring 37% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 70 | 48 | 0.4 | 6% | 0 | 278 |
| Feb | 73 | 50 | 0.4 | 1% | <1 | 334 |
| Mar | 80 | 55 | 0.4 | 0% | 0 | 546 |
| Apr | 86 | 60 | 0.1 | 0% | 0 | 693 |
| May | 94 | 67 | 0.1 | 0% | 0 | 949 |
| Jun | 103 | 75 | 0.0 | 0% | 0 | 1175 |
| Jul | 107 | 83 | 0.2 | 0% | 0 | 1384 |
| Aug | 106 | 83 | 0.2 | 0% | 0 | 1389 |
| Sep | 101 | 78 | 0.7 | 0% | 0 | 1185 |
| Oct | 90 | 66 | 0.1 | 0% | 0 | 867 |
| Nov | 78 | 54 | 0.2 | 0% | 0 | 482 |
| Dec | 68 | 47 | 0.4 | 1% | 0 | 229 |
Monthly normals 1991–2020 at Yuma Mcas, AZ (213 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 Quartermaster Depot, AZ, 11 miles northeast of Somerton, has a 32°F night in 57% of winters against 8% here, and a coolest-month low 3°F colder (44°F).
When it snows in Somerton, Arizona
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Yuma Mcas, AZ, 7.3 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 85350 is 7 miles from Yuma Mcas, AZ, which stands at 213 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 85349 (San Luis). The 2023 USDA Plant Hardiness Zone Map lists ZIP 85350 in zone 10a, the band where the coldest night of the year averaged 30 to 35°F (-1.1 to 1.7°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.