Agua Dulce Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Alice Intl AP. 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 February 5 and the first fall freeze around December 10, a growing season of about 312 days.
- Median at 36°F
- last February 25, first November 27
- Median at 32°F
- last February 5, first December 10
- Median at 28°F
- last January 16, first December 27
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 | Mar 19 | Mar 10 | Mar 5 | Mar 1 | Feb 25 | Feb 20 | Feb 15 | Feb 8 | Jan 29 |
| 32°F | Mar 4 | Feb 25 | Feb 19 | Feb 12 | Feb 5 | Jan 29 | Jan 23 | Jan 15 | Dec 30 |
| 28°F | Feb 22 | Feb 11 | Feb 2 | Jan 25 | Jan 16 | Jan 8 | Jan 1 | Dec 24 | Dec 10 |
| 24°F | Feb 14 | Feb 1 | Jan 19 | Jan 10 | Jan 5 | Dec 31 | Dec 25 | Dec 17 | Dec 7 |
| 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 7 | Nov 14 | Nov 18 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 9 | Dec 19 |
| 32°F | Nov 16 | Nov 25 | Nov 30 | Dec 5 | Dec 10 | Dec 17 | Dec 23 | Jan 1 | Jan 13 |
| 28°F | Nov 28 | Dec 5 | Dec 14 | Dec 19 | Dec 27 | Jan 2 | Jan 8 | Jan 17 | Feb 3 |
| 24°F | Dec 6 | Dec 14 | Dec 20 | Dec 28 | Jan 1 | Jan 5 | Jan 12 | Jan 23 | Feb 13 |
| 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 | 312 | 300 | 293 | 285 | 278 | 271 | 264 | 256 | 246 |
| 32°F | 353 | 340 | 330 | 321 | 312 | 303 | 295 | 285 | 273 |
| 28°F | 365 | 365 | 365 | 358 | 349 | 340 | 332 | 319 | 304 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 360 | 342 |
| 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
- 100% of years
- 32°F or colder
- 97% of years
- 28°F or colder
- 69% of years
- 24°F or colder
- 25% of years
- 20°F or colder
- 2% 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
- 885
- Cooling degree days, base 65°F
- 3,764
- Growing degree days, base 40°F
- 12,009
- Growing degree days, base 45°F
- 10,203
- Growing degree days, base 50°F
- 8,438
- Growing degree days, base 55°F
- 6,754
- Growing degree days, base 60°F
- 5,189
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 279 | 33 | 255 |
| February | 167 | 65 | 335 |
| March | 75 | 148 | 541 |
| April | 13 | 268 | 705 |
| May | 0 | 447 | 911 |
| June | 0 | 568 | 1,019 |
| July | 0 | 632 | 1,097 |
| August | 0 | 652 | 1,118 |
| September | 0 | 495 | 945 |
| October | 11 | 298 | 752 |
| November | 99 | 110 | 467 |
| December | 240 | 48 | 294 |
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 12.3 km from Agua Dulce. 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 USW00012932 (Alice Intl AP). Public domain.