Salisbury Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Salisbury. 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 3 and the first fall freeze around November 7, a growing season of about 217 days.
- Median at 36°F
- last April 17, first October 27
- Median at 32°F
- last April 3, first November 7
- Median at 28°F
- last March 21, first November 21
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 | May 8 | May 1 | Apr 24 | Apr 21 | Apr 17 | Apr 12 | Apr 9 | Apr 5 | Mar 31 |
| 32°F | Apr 25 | Apr 16 | Apr 9 | Apr 5 | Apr 3 | Mar 31 | Mar 28 | Mar 24 | Mar 18 |
| 28°F | Apr 6 | Mar 31 | Mar 29 | Mar 25 | Mar 21 | Mar 18 | Mar 15 | Mar 11 | Mar 4 |
| 24°F | Mar 27 | Mar 21 | Mar 17 | Mar 13 | Mar 10 | Mar 6 | Mar 2 | Feb 27 | Feb 20 |
| 20°F | Mar 15 | Mar 10 | Mar 5 | Mar 1 | Feb 26 | Feb 21 | Feb 16 | Feb 9 | Feb 2 |
| 16°F | Mar 3 | Feb 26 | Feb 19 | Feb 13 | Feb 7 | Feb 3 | Jan 30 | Jan 22 | Jan 12 |
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 14 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 9 |
| 32°F | Oct 27 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 13 | Nov 18 | Nov 23 |
| 28°F | Nov 4 | Nov 10 | Nov 13 | Nov 18 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 7 |
| 24°F | Nov 18 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 9 | Dec 14 | Dec 20 | Dec 27 |
| 20°F | Dec 2 | Dec 8 | Dec 15 | Dec 20 | Dec 24 | Dec 29 | Jan 2 | Jan 8 | Jan 16 |
| 16°F | Dec 12 | Dec 22 | Dec 28 | Jan 2 | Jan 7 | Jan 12 | Jan 17 | Jan 23 | Feb 1 |
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 | 214 | 208 | 202 | 197 | 193 | 189 | 183 | 178 | 170 |
| 32°F | 239 | 232 | 227 | 222 | 217 | 213 | 208 | 203 | 194 |
| 28°F | 268 | 261 | 254 | 249 | 244 | 239 | 234 | 228 | 218 |
| 24°F | 300 | 290 | 282 | 277 | 271 | 266 | 260 | 253 | 244 |
| 20°F | 326 | 318 | 311 | 305 | 300 | 295 | 289 | 281 | 273 |
| 16°F | 363 | 345 | 335 | 330 | 324 | 319 | 312 | 306 | 297 |
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
- 92% 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
- 3,764
- Cooling degree days, base 65°F
- 1,499
- Growing degree days, base 40°F
- 7,229
- Growing degree days, base 45°F
- 5,761
- Growing degree days, base 50°F
- 4,456
- Growing degree days, base 55°F
- 3,307
- Growing degree days, base 60°F
- 2,324
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 826 | 0 | 20 |
| February | 689 | 0 | 19 |
| March | 553 | 3 | 78 |
| April | 254 | 31 | 253 |
| May | 81 | 114 | 498 |
| June | 8 | 294 | 736 |
| July | 0 | 439 | 903 |
| August | 0 | 371 | 835 |
| September | 18 | 204 | 636 |
| October | 186 | 42 | 329 |
| November | 446 | 4 | 112 |
| December | 704 | 0 | 35 |
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 1 km from Salisbury. 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 USC00188000 (Salisbury). Public domain.