El Prado Estates Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Yuma Quartermaster Depot. A median date has an even chance of a later freeze in spring, or an earlier one in fall.
The last spring freeze typically comes around January 8 and the first fall freeze around December 28, a growing season of about 362 days.
- Median at 36°F
- last January 28, first December 16
- Median at 32°F
- last January 8, first December 28
- Median at 28°F
- last January 1, first December 31
Last freeze in spring
The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 28 | Feb 21 | Feb 13 | Feb 5 | Jan 28 | Jan 16 | Jan 9 | Jan 2 | Dec 25 |
| 32°F | Feb 19 | Feb 7 | Jan 31 | Jan 17 | Jan 8 | Jan 2 | Dec 31 | Dec 25 | Dec 17 |
| 28°F | Feb 16 | Jan 30 | Jan 17 | Jan 6 | Jan 1 | Dec 31 | Dec 28 | Dec 23 | Dec 19 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
First freeze in fall
The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 29 | Dec 5 | Dec 8 | Dec 12 | Dec 16 | Dec 19 | Dec 23 | Dec 28 | Jan 5 |
| 32°F | Dec 11 | Dec 16 | Dec 21 | Dec 26 | Dec 28 | Jan 1 | Jan 7 | Jan 19 | Feb 7 |
| 28°F | Dec 16 | Dec 22 | Dec 25 | Dec 29 | Dec 31 | Jan 1 | Jan 6 | Jan 28 | Feb 10 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
Growing season length
Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | 356 | 347 | 339 | 332 | 324 | 316 | 307 | 297 | 285 |
| 32°F | 365 | 365 | 365 | 365 | 362 | 355 | 349 | 339 | 323 |
| 28°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 353 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 20°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
How often it gets that cold
The share of years with at least one night at or below each temperature.
- 36°F or colder
- 96% of years
- 32°F or colder
- 57% of years
- 28°F or colder
- 19% of years
- 24°F or colder
- 5% of years
- 20°F or colder
- 0% of years
- 16°F or colder
- 0% of years
Degree days
A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.
- Heating degree days, base 65°F
- 794
- Cooling degree days, base 65°F
- 4,285
- Growing degree days, base 40°F
- 12,616
- Growing degree days, base 45°F
- 10,794
- Growing degree days, base 50°F
- 8,984
- Growing degree days, base 55°F
- 7,241
- Growing degree days, base 60°F
- 5,652
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 226 | 4 | 250 |
| February | 139 | 20 | 303 |
| March | 52 | 112 | 526 |
| April | 12 | 233 | 671 |
| May | 1 | 447 | 911 |
| June | 0 | 679 | 1,129 |
| July | 0 | 851 | 1,316 |
| August | 0 | 877 | 1,342 |
| September | 0 | 641 | 1,091 |
| October | 3 | 343 | 804 |
| November | 89 | 77 | 439 |
| December | 272 | 1 | 202 |
What this means
NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.
The station is 9.7 km from El Prado Estates. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.
More
Sources
NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00029656 (Yuma Quartermaster Depot). Public domain.