Sharon Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Laurel. 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 12 and the first fall freeze around November 12, a growing season of about 244 days.
- Median at 36°F
- last March 28, first November 2
- Median at 32°F
- last March 12, first November 12
- Median at 28°F
- last February 28, first November 23
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 14 | Apr 7 | Apr 4 | Mar 31 | Mar 28 | Mar 24 | Mar 19 | Mar 14 | Mar 7 |
| 32°F | Apr 1 | Mar 26 | Mar 20 | Mar 16 | Mar 12 | Mar 8 | Mar 4 | Feb 28 | Feb 22 |
| 28°F | Mar 18 | Mar 12 | Mar 8 | Mar 3 | Feb 28 | Feb 24 | Feb 18 | Feb 10 | Jan 31 |
| 24°F | Mar 9 | Mar 1 | Feb 24 | Feb 18 | Feb 11 | Feb 3 | Jan 31 | Jan 24 | Jan 12 |
| 20°F | Feb 26 | Feb 16 | Feb 4 | Jan 31 | Jan 27 | Jan 21 | Jan 15 | Jan 7 | Dec 31 |
| 16°F | Feb 12 | Feb 2 | Jan 29 | Jan 24 | Jan 20 | Jan 13 | Jan 8 | Jan 3 | Dec 25 |
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 21 | Oct 25 | Oct 28 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 18 |
| 32°F | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Dec 1 |
| 28°F | Nov 4 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 28 | Dec 3 | Dec 8 | Dec 21 |
| 24°F | Nov 16 | Nov 25 | Dec 1 | Dec 5 | Dec 11 | Dec 21 | Dec 30 | Jan 4 | Jan 14 |
| 20°F | Dec 1 | Dec 8 | Dec 20 | Dec 29 | Jan 1 | Jan 5 | Jan 9 | Jan 17 | Jan 27 |
| 16°F | Dec 13 | Dec 26 | Jan 1 | Jan 4 | Jan 8 | Jan 13 | Jan 19 | Jan 26 | 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 | 242 | 234 | 228 | 223 | 218 | 214 | 209 | 205 | 197 |
| 32°F | 273 | 262 | 255 | 249 | 244 | 238 | 232 | 226 | 219 |
| 28°F | 303 | 294 | 285 | 278 | 271 | 265 | 258 | 251 | 242 |
| 24°F | 341 | 331 | 320 | 312 | 305 | 298 | 289 | 280 | 267 |
| 20°F | 365 | 365 | 356 | 347 | 338 | 332 | 323 | 312 | 299 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 364 | 354 | 343 | 331 |
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
- 98% of years
- 20°F or colder
- 82% of years
- 16°F or colder
- 48% 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
- 2,138
- Cooling degree days, base 65°F
- 2,342
- Growing degree days, base 40°F
- 9,406
- Growing degree days, base 45°F
- 7,711
- Growing degree days, base 50°F
- 6,139
- Growing degree days, base 55°F
- 4,710
- Growing degree days, base 60°F
- 3,438
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 554 | 4 | 86 |
| February | 385 | 7 | 129 |
| March | 236 | 32 | 289 |
| April | 86 | 90 | 457 |
| May | 11 | 255 | 710 |
| June | 0 | 432 | 882 |
| July | 0 | 519 | 984 |
| August | 0 | 502 | 967 |
| September | 3 | 349 | 796 |
| October | 85 | 124 | 507 |
| November | 296 | 19 | 213 |
| December | 484 | 8 | 120 |
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 12.9 km from Sharon. 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 USC00224939 (Laurel). Public domain.