Espy Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Bear Gap. 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 27 and the first fall freeze around October 20, a growing season of about 172 days.
- Median at 36°F
- last May 9, first October 6
- Median at 32°F
- last April 27, first October 20
- Median at 28°F
- last April 13, first November 2
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 26 | May 21 | May 17 | May 13 | May 9 | May 6 | May 1 | Apr 28 | Apr 22 |
| 32°F | May 15 | May 9 | May 4 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 17 | Apr 12 |
| 28°F | May 3 | Apr 25 | Apr 20 | Apr 16 | Apr 13 | Apr 9 | Apr 6 | Apr 2 | Mar 28 |
| 24°F | Apr 14 | Apr 9 | Apr 5 | Apr 2 | Mar 31 | Mar 29 | Mar 26 | Mar 21 | Mar 15 |
| 20°F | Apr 2 | Mar 30 | Mar 27 | Mar 24 | Mar 21 | Mar 17 | Mar 14 | Mar 10 | Mar 3 |
| 16°F | Mar 27 | Mar 21 | Mar 18 | Mar 15 | Mar 11 | Mar 8 | Mar 4 | Feb 28 | Feb 22 |
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 24 | Sep 28 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 13 | Oct 17 | Oct 22 |
| 32°F | Oct 4 | Oct 8 | Oct 12 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Nov 1 | Nov 5 |
| 28°F | Oct 16 | Oct 22 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 18 |
| 24°F | Nov 1 | Nov 4 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | Nov 26 | Dec 2 |
| 20°F | Nov 11 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 9 | Dec 15 |
| 16°F | Nov 21 | Nov 27 | Dec 1 | Dec 6 | Dec 10 | Dec 14 | Dec 20 | Dec 24 | Dec 30 |
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 | 171 | 163 | 157 | 153 | 148 | 144 | 139 | 134 | 126 |
| 32°F | 195 | 188 | 183 | 178 | 172 | 168 | 163 | 159 | 150 |
| 28°F | 225 | 217 | 212 | 207 | 202 | 197 | 192 | 186 | 178 |
| 24°F | 249 | 242 | 236 | 232 | 228 | 224 | 220 | 215 | 208 |
| 20°F | 277 | 266 | 260 | 256 | 251 | 247 | 242 | 236 | 229 |
| 16°F | 298 | 291 | 285 | 279 | 273 | 268 | 263 | 257 | 249 |
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
- 5,922
- Cooling degree days, base 65°F
- 654
- Growing degree days, base 40°F
- 5,090
- Growing degree days, base 45°F
- 3,918
- Growing degree days, base 50°F
- 2,888
- Growing degree days, base 55°F
- 1,998
- Growing degree days, base 60°F
- 1,248
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,176 | 0 | 2 |
| February | 977 | 0 | 4 |
| March | 832 | 0 | 21 |
| April | 465 | 6 | 106 |
| May | 197 | 34 | 313 |
| June | 35 | 126 | 542 |
| July | 4 | 236 | 697 |
| August | 11 | 177 | 631 |
| September | 111 | 67 | 408 |
| October | 401 | 7 | 141 |
| November | 707 | 0 | 22 |
| December | 1,006 | 0 | 3 |
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 21.9 km from Espy. 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 USC00360457 (Bear Gap). Public domain.