Gorman Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Raleigh Durham 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 March 31 and the first fall freeze around November 4, a growing season of about 219 days.
- Median at 36°F
- last April 13, first October 27
- Median at 32°F
- last March 31, first November 4
- Median at 28°F
- last March 18, first November 16
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 28 | Apr 22 | Apr 18 | Apr 16 | Apr 13 | Apr 10 | Apr 7 | Apr 3 | Mar 29 |
| 32°F | Apr 16 | Apr 11 | Apr 6 | Apr 3 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 15 |
| 28°F | Apr 3 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 10 | Mar 4 | Feb 25 |
| 24°F | Mar 24 | Mar 18 | Mar 13 | Mar 7 | Mar 2 | Feb 27 | Feb 21 | Feb 14 | Feb 4 |
| 20°F | Mar 11 | Mar 3 | Feb 26 | Feb 19 | Feb 12 | Feb 5 | Jan 31 | Jan 26 | Jan 14 |
| 16°F | Feb 28 | Feb 14 | Feb 4 | Jan 31 | Jan 27 | Jan 22 | Jan 17 | Jan 10 | Jan 1 |
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 15 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 29 | Oct 31 | Nov 3 | Nov 6 |
| 32°F | Oct 23 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 17 |
| 28°F | Nov 2 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 19 | Nov 24 | Nov 30 | Dec 5 |
| 24°F | Nov 12 | Nov 20 | Nov 25 | Nov 30 | Dec 3 | Dec 6 | Dec 12 | Dec 20 | Jan 1 |
| 20°F | Nov 30 | Dec 5 | Dec 11 | Dec 17 | Dec 24 | Dec 31 | Jan 4 | Jan 11 | Jan 20 |
| 16°F | Dec 13 | Dec 23 | Jan 1 | Jan 3 | Jan 8 | Jan 14 | Jan 18 | Jan 24 | Feb 2 |
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 | 215 | 209 | 205 | 200 | 196 | 193 | 188 | 183 | 177 |
| 32°F | 241 | 233 | 227 | 223 | 219 | 214 | 210 | 204 | 198 |
| 28°F | 272 | 262 | 256 | 250 | 245 | 241 | 235 | 228 | 221 |
| 24°F | 308 | 297 | 290 | 283 | 277 | 271 | 264 | 258 | 248 |
| 20°F | 343 | 333 | 327 | 319 | 310 | 305 | 297 | 288 | 278 |
| 16°F | 365 | 365 | 356 | 348 | 341 | 334 | 328 | 319 | 306 |
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
- 98% of years
- 16°F or colder
- 81% 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
- 3,153
- Cooling degree days, base 65°F
- 1,805
- Growing degree days, base 40°F
- 7,992
- Growing degree days, base 45°F
- 6,436
- Growing degree days, base 50°F
- 5,037
- Growing degree days, base 55°F
- 3,795
- Growing degree days, base 60°F
- 2,721
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 718 | 1 | 37 |
| February | 562 | 2 | 53 |
| March | 421 | 12 | 152 |
| April | 180 | 54 | 337 |
| May | 47 | 166 | 585 |
| June | 3 | 354 | 801 |
| July | 0 | 480 | 945 |
| August | 0 | 428 | 893 |
| September | 15 | 243 | 678 |
| October | 160 | 56 | 370 |
| November | 412 | 7 | 132 |
| December | 636 | 3 | 55 |
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 16.5 km from Gorman. 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 USW00013722 (Raleigh Durham Intl AP). Public domain.