Pine Haven Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Devils Twr #2. 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 23 and the first fall freeze around September 20, a growing season of about 118 days.
- Median at 36°F
- last June 4, first September 8
- Median at 32°F
- last May 23, first September 20
- Median at 28°F
- last May 12, first October 1
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 | Jun 23 | Jun 17 | Jun 12 | Jun 8 | Jun 4 | Jun 1 | May 29 | May 26 | May 22 |
| 32°F | Jun 6 | May 31 | May 28 | May 26 | May 23 | May 21 | May 19 | May 16 | May 12 |
| 28°F | May 24 | May 20 | May 17 | May 14 | May 12 | May 10 | May 7 | May 4 | May 2 |
| 24°F | May 13 | May 10 | May 7 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 19 |
| 20°F | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 14 | Apr 11 | Apr 5 |
| 16°F | Apr 26 | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 5 | Apr 2 | Mar 30 | Mar 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 | Aug 27 | Sep 1 | Sep 3 | Sep 6 | Sep 8 | Sep 12 | Sep 15 | Sep 19 | Sep 23 |
| 32°F | Sep 4 | Sep 9 | Sep 14 | Sep 17 | Sep 20 | Sep 23 | Sep 27 | Sep 30 | Oct 4 |
| 28°F | Sep 15 | Sep 21 | Sep 25 | Sep 29 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 14 |
| 24°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 24 |
| 20°F | Oct 4 | Oct 10 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Nov 2 |
| 16°F | Oct 15 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 3 | Nov 7 | Nov 12 |
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 | 114 | 108 | 103 | 99 | 95 | 91 | 86 | 79 | 72 |
| 32°F | 137 | 130 | 126 | 122 | 118 | 113 | 108 | 103 | 95 |
| 28°F | 158 | 151 | 147 | 144 | 141 | 137 | 132 | 127 | 120 |
| 24°F | 180 | 174 | 169 | 165 | 162 | 157 | 153 | 147 | 140 |
| 20°F | 204 | 197 | 192 | 187 | 183 | 179 | 174 | 168 | 161 |
| 16°F | 228 | 220 | 214 | 209 | 205 | 200 | 196 | 190 | 182 |
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
- 7,912
- Cooling degree days, base 65°F
- 439
- Growing degree days, base 40°F
- 3,937
- Growing degree days, base 45°F
- 2,956
- Growing degree days, base 50°F
- 2,120
- Growing degree days, base 55°F
- 1,422
- Growing degree days, base 60°F
- 860
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,364 | 0 | 0 |
| February | 1,152 | 0 | 0 |
| March | 958 | 0 | 8 |
| April | 668 | 0 | 35 |
| May | 397 | 8 | 156 |
| June | 133 | 58 | 381 |
| July | 28 | 183 | 620 |
| August | 46 | 155 | 574 |
| September | 233 | 34 | 283 |
| October | 623 | 2 | 60 |
| November | 989 | 0 | 3 |
| December | 1,322 | 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 26.2 km from Pine Haven. 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 USC00482466 (Devils Twr #2). Public domain.