USDA Hardiness Zone 10a
Frost Dates for 86442 — Bullhead City, Arizona
NOAA 1991–2020 normals from Bullhead City, AZ (531 ft), 3 miles northeast.
Updated
A freeze (32°F) reaches Bullhead City in 67% of winters. When it does, the first fall frost comes around December 23 and the last spring frost around January 4; after February 5 the chance of another is under 7%.
- Last spring frost
- January 4
- First fall frost
- December 23
- Winters with a freeze
- 67%
- Hardiness zone
- 10a
50%, in freezing years
50%, in freezing years
32°F or below, 1991–2020
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 30 observed
NOAA normal
Frost risk by date in Bullhead City
In the 67% of winters that bring a 32°F night, half of springs at Bullhead City, AZ see their last 32°F night by January 4; only one in ten is past it by December 12, and one in ten still has one after February 5. Counting the winters with no freeze at all, the risk of a 32°F night after February 5 is under 7% and after January 4 33%. The 32 days between the even-odds date and the one-in-ten date is wider than at 87% 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 23 in half of years, as early as December 1 one year in ten, and holds off past January 23 one year in ten. A hard freeze of 28°F is less common: it came in 18% of winters. The freeze-free season lasts 356 days in a typical year, longer than at 98% of the 98 Arizona stations; it reaches 365 days one year in ten and falls short of 323 one year in ten. On average 2 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 28 days longer, to about February 1, and return around December 11. A 24°F night is unusual: 2% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F97% of yrs | Dec 31 | Jan 9 | Jan 18 | Jan 26 | Feb 1 | Feb 7 | Feb 14 | Feb 23 | Feb 28 |
| 32°F67% of yrs | Dec 12 | Dec 20 | Dec 27 | Dec 31 | Jan 4 | Jan 9 | Jan 15 | Jan 26 | Feb 5 |
| 28°F18% 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°F97% of yrs | Nov 24 | Nov 30 | Dec 3 | Dec 6 | Dec 11 | Dec 15 | Dec 20 | Dec 26 | Jan 2 |
| 32°F67% of yrs | Dec 1 | Dec 8 | Dec 13 | Dec 18 | Dec 23 | Dec 27 | Jan 1 | Jan 9 | Jan 23 |
| 28°F18% of yrs | too rare for a date | ||||||||
| 24°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Bullhead City, 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 86442 →Compare Bullhead City with another place →
Weather by month in Bullhead City
July is the warmest month at Bullhead City, AZ, averaging 111°F by day and 81°F at night; December is the coldest at 64°F and 44°F. From February to November the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 8,922 growing degree days a year (base 50°F), more than at 95% of the 102 Arizona stations. 41% of them (3,679) have built up by the end of June, and July adds the most, 1,423. Precipitation totals 5.5 inches a year, most in February (1.2") and least in June (0.0"); May to September bring 18% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 65 | 45 | 1.0 | 34% | 1 | 167 |
| Feb | 70 | 47 | 1.2 | 8% | <1 | 235 |
| Mar | 79 | 51 | 0.8 | 0% | 0 | 453 |
| Apr | 87 | 57 | 0.1 | 0% | 0 | 662 |
| May | 96 | 66 | 0.1 | 0% | 0 | 963 |
| Jun | 107 | 73 | 0.0 | 0% | 0 | 1200 |
| Jul | 111 | 81 | 0.2 | 0% | 0 | 1423 |
| Aug | 109 | 81 | 0.5 | 0% | 0 | 1397 |
| Sep | 103 | 73 | 0.2 | 0% | 0 | 1130 |
| Oct | 89 | 61 | 0.5 | 0% | 0 | 784 |
| Nov | 74 | 51 | 0.4 | 6% | <1 | 373 |
| Dec | 64 | 44 | 0.5 | 42% | 1 | 138 |
Monthly normals 1991–2020 at Bullhead City, AZ (531 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, Laughlin, NV, 5 miles north of Bullhead City, has a last frost 1 day later (January 5), a first frost 1 day later (December 24), a season 2 days shorter.
When it snows in Bullhead City, Arizona
Measurable snow is rare here: only 0 of 30 winters from 1991 to 2020 recorded 0.1 inch or more at Laughlin, NV, 5 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 86442 is 3 miles from Bullhead City, AZ, which stands at 531 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86442 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.