Pisgah Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Scottsboro 2 Ne. 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 April 2 and the first fall freeze around October 30, a growing season of about 210 days.
- Median at 36°F
- last April 15, first October 23
- Median at 32°F
- last April 2, first October 30
- Median at 28°F
- last March 20, first November 8
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 | Apr 29 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 5 | Mar 31 |
| 32°F | Apr 19 | Apr 13 | Apr 9 | Apr 6 | Apr 2 | Mar 31 | Mar 28 | Mar 24 | Mar 18 |
| 28°F | Apr 7 | Apr 1 | Mar 28 | Mar 25 | Mar 20 | Mar 17 | Mar 13 | Mar 9 | Mar 3 |
| 24°F | Mar 26 | Mar 20 | Mar 16 | Mar 12 | Mar 8 | Mar 4 | Feb 28 | Feb 22 | Feb 11 |
| 20°F | Mar 15 | Mar 7 | Mar 1 | Feb 25 | Feb 19 | Feb 13 | Feb 6 | Jan 31 | Jan 19 |
| 16°F | Mar 3 | Feb 22 | Feb 13 | Feb 7 | Feb 1 | Jan 29 | Jan 22 | Jan 15 | Jan 5 |
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 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 25 | Oct 27 | Oct 30 | Nov 3 |
| 32°F | Oct 18 | Oct 22 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 12 |
| 28°F | Oct 26 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 10 | Nov 15 | Nov 20 | Nov 27 |
| 24°F | Nov 5 | Nov 9 | Nov 13 | Nov 17 | Nov 21 | Nov 27 | Dec 2 | Dec 8 | Dec 19 |
| 20°F | Nov 15 | Nov 23 | Nov 30 | Dec 3 | Dec 9 | Dec 17 | Dec 26 | Jan 1 | Jan 8 |
| 16°F | Dec 1 | Dec 8 | Dec 17 | Dec 26 | Jan 1 | Jan 6 | Jan 10 | Jan 17 | Jan 29 |
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 | 209 | 203 | 198 | 193 | 189 | 185 | 181 | 177 | 170 |
| 32°F | 232 | 224 | 219 | 214 | 210 | 206 | 201 | 196 | 188 |
| 28°F | 258 | 251 | 244 | 238 | 233 | 228 | 223 | 218 | 209 |
| 24°F | 293 | 283 | 274 | 269 | 263 | 258 | 251 | 244 | 235 |
| 20°F | 331 | 318 | 308 | 302 | 295 | 288 | 280 | 271 | 261 |
| 16°F | 365 | 348 | 338 | 333 | 327 | 319 | 312 | 304 | 291 |
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
- 100% of years
- 28°F or colder
- 100% of years
- 24°F or colder
- 100% of years
- 20°F or colder
- 99% of years
- 16°F or colder
- 89% 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
- 3,339
- Cooling degree days, base 65°F
- 1,522
- Growing degree days, base 40°F
- 7,581
- Growing degree days, base 45°F
- 6,048
- Growing degree days, base 50°F
- 4,660
- Growing degree days, base 55°F
- 3,443
- Growing degree days, base 60°F
- 2,401
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 761 | 0 | 32 |
| February | 580 | 1 | 46 |
| March | 419 | 4 | 137 |
| April | 185 | 30 | 308 |
| May | 51 | 130 | 544 |
| June | 1 | 302 | 751 |
| July | 0 | 408 | 873 |
| August | 0 | 391 | 855 |
| September | 19 | 210 | 642 |
| October | 183 | 44 | 337 |
| November | 468 | 3 | 90 |
| December | 673 | 0 | 45 |
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 13.9 km from Pisgah. 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 USW00063896 (Scottsboro 2 Ne). Public domain.