USDA Hardiness Zone 9a
Frost Dates for 85346 — Quartzsite, Arizona
NOAA 1991–2020 normals from Quartzsite, AZ (875 ft), under a mile northeast.
Updated
In Quartzsite, the last spring frost (32°F) is around January 28 in half of years and has passed by February 24 in nine years out of ten. The first fall frost comes around December 6, as early as November 22 one year in ten, leaving a typical freeze-free season of 315 days (NOAA, Quartzsite, AZ).
- Last spring frost
- January 28
- First fall frost
- December 6
- Growing season
- 315 days
- Hardiness zone
- 9a
50% probability
50% probability
freeze-free, 50%
20 to 25°F (-6.7 to -3.9°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 4%
- Snow per year
- 0.2"
median, 1991–2020
median, 1991–2020
1 of 24 observed
NOAA normal
Frost risk by date in Quartzsite
Half of springs at Quartzsite, AZ see their last 32°F night by January 28; only one in ten is past it by December 31, and one in ten still has one after February 24. Planting tender crops after February 9 leaves a 30% risk of a frost on them, after February 14 20%, and after February 24 10%. The 27 days between the even-odds date and the one-in-ten date is wider than at 71% 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 6 in half of years, as early as November 22 one year in ten, and holds off past December 26 one year in ten. A hard freeze of 28°F follows 15 days later, around December 21; in spring the one-in-ten date for 28°F is February 5, 19 days before the 32°F one. The freeze-free season lasts 315 days in a typical year, longer than at 80% of the 98 Arizona stations; it reaches 343 days one year in ten and falls short of 283 one year in ten. On average 12 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 20 days longer, to about February 17, and return around November 27. A 24°F night is unusual: 22% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jan 25 | Feb 2 | Feb 8 | Feb 12 | Feb 17 | Feb 22 | Feb 26 | Mar 3 | Mar 7 |
| 32°F99% of yrs | Dec 31 | Jan 8 | Jan 15 | Jan 22 | Jan 28 | Feb 3 | Feb 9 | Feb 14 | Feb 24 |
| 28°F73% of yrs | Dec 13 | Dec 22 | Dec 30 | Jan 3 | Jan 7 | Jan 11 | Jan 17 | Jan 26 | Feb 5 |
| 24°F22% 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 13 | Nov 17 | Nov 21 | Nov 23 | Nov 27 | Nov 30 | Dec 2 | Dec 6 | Dec 12 |
| 32°F99% of yrs | Nov 22 | Nov 27 | Dec 1 | Dec 4 | Dec 6 | Dec 10 | Dec 14 | Dec 19 | Dec 26 |
| 28°F73% of yrs | Dec 1 | Dec 6 | Dec 11 | Dec 16 | Dec 21 | Dec 26 | Dec 30 | Jan 4 | Jan 13 |
| 24°F22% of yrs | too rare for a date | ||||||||
| 20°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Quartzsite, 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 85346 →Compare Quartzsite with another place →
Weather by month in Quartzsite
July is the warmest month at Quartzsite, AZ, averaging 109°F by day and 82°F at night; December is the coldest at 65°F and 39°F. A freezing night is all but certain in December (a 90% chance or more). From March to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 41% of years.
Warmth for growing adds up to 8,760 growing degree days a year (base 50°F), more than at 90% of the 102 Arizona stations. 41% of them (3,616) have built up by the end of June, and July adds the most, 1,411. Precipitation totals 4.8 inches a year, most in January (0.7") and least in April (0.1"); May to September bring 35% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 67 | 40 | 0.7 | 80% | 4 | 134 |
| Feb | 71 | 44 | 0.7 | 41% | 1 | 225 |
| Mar | 79 | 51 | 0.5 | 6% | <1 | 456 |
| Apr | 87 | 57 | 0.1 | 0% | 0 | 651 |
| May | 95 | 66 | 0.1 | 0% | 0 | 949 |
| Jun | 105 | 75 | 0.1 | 0% | 0 | 1201 |
| Jul | 109 | 82 | 0.5 | 0% | 0 | 1411 |
| Aug | 108 | 82 | 0.5 | 0% | 0 | 1389 |
| Sep | 102 | 74 | 0.5 | 0% | 0 | 1135 |
| Oct | 90 | 60 | 0.2 | 0% | <1 | 763 |
| Nov | 76 | 47 | 0.3 | 28% | 1 | 344 |
| Dec | 65 | 39 | 0.6 | 90% | 6 | 102 |
Monthly normals 1991–2020 at Quartzsite, AZ (875 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, Blythe, CA, 21 miles west of Quartzsite and 607 feet lower, has a last frost 3 days earlier (January 25), a first frost 6 days later (December 12), a season 10 days longer.
When it snows in Quartzsite, Arizona
Measurable snow is rare here: only 1 of 24 winters from 1991 to 2020 recorded 0.1 inch or more at Quartzsite, AZ, 0.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 85346
| When | What to do |
|---|---|
| November 19 – December 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 3 – December 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| December 31 – January 14 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| January 28 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 6 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 85346 is under a mile from Quartzsite, AZ, which stands at 875 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85346 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°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.