Hackberry Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Hackberry 8 Ssw. 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 3 and the first fall freeze around December 24, a growing season of about 323 days.
- Median at 36°F
- last February 23, first December 5
- Median at 32°F
- last February 3, first December 24
- Median at 28°F
- last January 22, first January 3
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 18 | Mar 12 | Mar 6 | Mar 1 | Feb 23 | Feb 18 | Feb 11 | Feb 2 | Jan 26 |
| 32°F | Mar 9 | Mar 1 | Feb 21 | Feb 12 | Feb 3 | Jan 29 | Jan 23 | Jan 16 | Jan 6 |
| 28°F | Feb 26 | Feb 10 | Feb 1 | Jan 29 | Jan 22 | Jan 17 | Jan 10 | Jan 4 | Dec 24 |
| 24°F | Feb 9 | Feb 1 | Jan 26 | Jan 18 | Jan 11 | Jan 5 | Jan 1 | Dec 27 | Dec 17 |
| 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 13 | Nov 19 | Nov 26 | Dec 1 | Dec 5 | Dec 8 | Dec 13 | Dec 22 | Jan 2 |
| 32°F | Nov 26 | Dec 6 | Dec 10 | Dec 17 | Dec 24 | Dec 30 | Jan 4 | Jan 11 | Jan 22 |
| 28°F | Dec 10 | Dec 17 | Dec 25 | Dec 30 | Jan 3 | Jan 9 | Jan 16 | Jan 24 | Feb 1 |
| 24°F | Dec 13 | Dec 22 | Dec 28 | Jan 1 | Jan 5 | Jan 11 | Jan 18 | Jan 26 | Feb 3 |
| 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 | 325 | 312 | 304 | 296 | 288 | 281 | 273 | 264 | 252 |
| 32°F | 359 | 347 | 338 | 332 | 323 | 313 | 305 | 295 | 282 |
| 28°F | 365 | 365 | 365 | 362 | 355 | 348 | 340 | 332 | 315 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 358 | 345 |
| 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
- 93% of years
- 28°F or colder
- 62% of years
- 24°F or colder
- 27% of years
- 20°F or colder
- 5% 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
- 1,342
- Cooling degree days, base 65°F
- 3,028
- Growing degree days, base 40°F
- 10,829
- Growing degree days, base 45°F
- 9,050
- Growing degree days, base 50°F
- 7,340
- Growing degree days, base 55°F
- 5,746
- Growing degree days, base 60°F
- 4,300
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 396 | 6 | 147 |
| February | 266 | 12 | 200 |
| March | 146 | 50 | 380 |
| April | 31 | 149 | 569 |
| May | 2 | 357 | 820 |
| June | 0 | 513 | 963 |
| July | 0 | 583 | 1,048 |
| August | 0 | 586 | 1,051 |
| September | 0 | 459 | 909 |
| October | 22 | 237 | 681 |
| November | 148 | 61 | 375 |
| December | 332 | 16 | 197 |
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 13.2 km from Hackberry. 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 USC00163979 (Hackberry 8 Ssw). Public domain.