Laurel Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Salisbury 2N. 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 November 10, a growing season of about 222 days.
- Median at 36°F
- last April 15, first October 31
- Median at 32°F
- last April 2, first November 10
- Median at 28°F
- last March 20, first November 24
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 23 | Apr 20 | Apr 17 | Apr 15 | Apr 12 | Apr 8 | Apr 4 | Mar 30 |
| 32°F | Apr 16 | Apr 11 | Apr 7 | Apr 5 | Apr 2 | Mar 30 | Mar 27 | Mar 22 | Mar 16 |
| 28°F | Apr 3 | Mar 30 | Mar 27 | Mar 23 | Mar 20 | Mar 17 | Mar 13 | Mar 9 | Mar 2 |
| 24°F | Mar 26 | Mar 20 | Mar 16 | Mar 13 | Mar 8 | Mar 4 | Feb 28 | Feb 24 | Feb 17 |
| 20°F | Mar 16 | Mar 10 | Mar 5 | Mar 1 | Feb 25 | Feb 20 | Feb 13 | Feb 6 | Jan 30 |
| 16°F | Mar 6 | Feb 28 | Feb 23 | Feb 15 | Feb 9 | Feb 2 | Jan 30 | Jan 24 | Jan 15 |
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 18 | Oct 22 | Oct 26 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 11 |
| 32°F | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 12 | Nov 16 | Nov 21 | Nov 27 |
| 28°F | Nov 8 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 13 |
| 24°F | Nov 18 | Nov 25 | Dec 1 | Dec 4 | Dec 7 | Dec 13 | Dec 18 | Dec 24 | Jan 1 |
| 20°F | Dec 3 | Dec 10 | Dec 17 | Dec 21 | Dec 27 | Jan 1 | Jan 4 | Jan 11 | Jan 20 |
| 16°F | Dec 18 | Dec 26 | Jan 1 | Jan 6 | Jan 10 | Jan 15 | Jan 19 | Jan 25 | Feb 3 |
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 | 219 | 213 | 208 | 203 | 199 | 196 | 191 | 185 | 177 |
| 32°F | 247 | 238 | 232 | 227 | 222 | 218 | 214 | 209 | 202 |
| 28°F | 275 | 266 | 259 | 254 | 249 | 244 | 239 | 234 | 226 |
| 24°F | 304 | 292 | 287 | 280 | 275 | 269 | 263 | 257 | 247 |
| 20°F | 330 | 321 | 311 | 306 | 300 | 295 | 290 | 282 | 274 |
| 16°F | 365 | 350 | 339 | 334 | 328 | 321 | 312 | 305 | 295 |
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
- 100% of years
- 16°F or colder
- 91% 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
- 3,799
- Cooling degree days, base 65°F
- 1,425
- Growing degree days, base 40°F
- 7,133
- Growing degree days, base 45°F
- 5,663
- Growing degree days, base 50°F
- 4,352
- Growing degree days, base 55°F
- 3,214
- Growing degree days, base 60°F
- 2,236
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 831 | 0 | 16 |
| February | 681 | 0 | 23 |
| March | 563 | 4 | 81 |
| April | 264 | 25 | 243 |
| May | 79 | 110 | 497 |
| June | 7 | 274 | 717 |
| July | 0 | 420 | 885 |
| August | 0 | 355 | 820 |
| September | 21 | 195 | 624 |
| October | 194 | 40 | 321 |
| November | 454 | 2 | 94 |
| December | 707 | 0 | 33 |
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 16.6 km from Laurel. 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 USC00188004 (Salisbury 2N). Public domain.