Lapel Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Anderson Sewage Plt. 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 19 and the first fall freeze around October 23, a growing season of about 186 days.
- Median at 36°F
- last April 30, first October 13
- Median at 32°F
- last April 19, first October 23
- Median at 28°F
- last April 5, first November 3
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 16 | May 10 | May 6 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 16 |
| 32°F | May 5 | Apr 30 | Apr 25 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 8 | Apr 3 |
| 28°F | Apr 25 | Apr 19 | Apr 14 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 27 | Mar 22 |
| 24°F | Apr 11 | Apr 4 | Mar 31 | Mar 29 | Mar 27 | Mar 23 | Mar 20 | Mar 16 | Mar 10 |
| 20°F | Mar 31 | Mar 26 | Mar 22 | Mar 19 | Mar 15 | Mar 12 | Mar 8 | Mar 4 | Feb 27 |
| 16°F | Mar 22 | Mar 17 | Mar 12 | Mar 9 | Mar 5 | Mar 2 | Feb 27 | Feb 21 | Feb 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 | Sep 30 | Oct 3 | Oct 7 | Oct 10 | Oct 13 | Oct 15 | Oct 19 | Oct 22 | Oct 26 |
| 32°F | Oct 7 | Oct 13 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 6 |
| 28°F | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 20 |
| 24°F | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 28 | Dec 3 |
| 20°F | Nov 9 | Nov 15 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 18 |
| 16°F | Nov 20 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 18 | Dec 23 | Dec 28 |
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 | 184 | 176 | 171 | 167 | 163 | 159 | 155 | 149 | 143 |
| 32°F | 208 | 201 | 195 | 191 | 186 | 182 | 176 | 170 | 162 |
| 28°F | 235 | 225 | 219 | 216 | 211 | 207 | 201 | 195 | 186 |
| 24°F | 261 | 253 | 247 | 241 | 236 | 231 | 226 | 219 | 210 |
| 20°F | 284 | 274 | 268 | 263 | 258 | 253 | 248 | 242 | 233 |
| 16°F | 305 | 296 | 290 | 284 | 279 | 275 | 269 | 263 | 253 |
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
- 100% 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
- 5,473
- Cooling degree days, base 65°F
- 977
- Growing degree days, base 40°F
- 5,802
- Growing degree days, base 45°F
- 4,565
- Growing degree days, base 50°F
- 3,464
- Growing degree days, base 55°F
- 2,495
- Growing degree days, base 60°F
- 1,665
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,153 | 0 | 3 |
| February | 936 | 0 | 7 |
| March | 742 | 2 | 47 |
| April | 388 | 11 | 156 |
| May | 150 | 80 | 402 |
| June | 19 | 213 | 643 |
| July | 3 | 291 | 753 |
| August | 5 | 247 | 707 |
| September | 76 | 113 | 489 |
| October | 334 | 20 | 205 |
| November | 667 | 1 | 44 |
| December | 1,001 | 0 | 7 |
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 12.2 km from Lapel. 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 USC00120177 (Anderson Sewage Plt). Public domain.