Everly Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Spencer Muni AP. 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 May 2 and the first fall freeze around October 2, a growing season of about 154 days.
- Median at 36°F
- last May 9, first September 24
- Median at 32°F
- last May 2, first October 2
- Median at 28°F
- last April 22, first October 12
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 22 | May 18 | May 14 | May 12 | May 9 | May 7 | May 5 | May 2 | Apr 28 |
| 32°F | May 15 | May 10 | May 7 | May 4 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 17 |
| 28°F | May 7 | May 2 | Apr 29 | Apr 25 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 8 |
| 24°F | Apr 29 | Apr 22 | Apr 19 | Apr 15 | Apr 12 | Apr 9 | Apr 6 | Apr 2 | Mar 29 |
| 20°F | Apr 20 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Apr 1 | Mar 29 | Mar 23 | Mar 16 |
| 16°F | Apr 11 | Apr 5 | Apr 2 | Mar 30 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 8 |
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 9 | Sep 14 | Sep 18 | Sep 20 | Sep 24 | Sep 27 | Sep 30 | Oct 3 | Oct 7 |
| 32°F | Sep 18 | Sep 22 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 16 |
| 28°F | Sep 26 | Oct 1 | Oct 5 | Oct 8 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
| 24°F | Oct 5 | Oct 12 | Oct 18 | Oct 21 | Oct 23 | Oct 25 | Oct 28 | Nov 1 | Nov 5 |
| 20°F | Oct 19 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 10 | Nov 15 |
| 16°F | Oct 27 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 11 | Nov 14 | Nov 18 | Nov 25 |
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 | 155 | 148 | 144 | 140 | 136 | 132 | 128 | 123 | 118 |
| 32°F | 173 | 166 | 161 | 157 | 154 | 150 | 146 | 141 | 134 |
| 28°F | 193 | 186 | 181 | 177 | 172 | 168 | 164 | 158 | 152 |
| 24°F | 214 | 207 | 202 | 197 | 193 | 188 | 184 | 177 | 170 |
| 20°F | 233 | 224 | 220 | 216 | 211 | 207 | 203 | 197 | 189 |
| 16°F | 251 | 243 | 237 | 232 | 227 | 224 | 219 | 213 | 204 |
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
- 7,353
- Cooling degree days, base 65°F
- 774
- Growing degree days, base 40°F
- 4,904
- Growing degree days, base 45°F
- 3,847
- Growing degree days, base 50°F
- 2,898
- Growing degree days, base 55°F
- 2,065
- Growing degree days, base 60°F
- 1,355
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,489 | 0 | 0 |
| February | 1,219 | 0 | 1 |
| March | 955 | 0 | 16 |
| April | 538 | 4 | 86 |
| May | 221 | 47 | 311 |
| June | 32 | 176 | 594 |
| July | 7 | 267 | 725 |
| August | 18 | 190 | 637 |
| September | 140 | 80 | 399 |
| October | 494 | 9 | 118 |
| November | 911 | 0 | 12 |
| December | 1,328 | 0 | 0 |
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 10.2 km from Everly. 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 USW00014972 (Spencer Muni AP). Public domain.