Liberty Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Eden-Liberty. 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 25 and the first fall freeze around September 26, a growing season of about 123 days.
- Median at 36°F
- last June 10, first September 15
- Median at 32°F
- last May 25, first September 26
- Median at 28°F
- last May 4, first October 7
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 26 | Jun 21 | Jun 17 | Jun 14 | Jun 10 | Jun 7 | Jun 4 | May 31 | May 23 |
| 32°F | Jun 16 | Jun 8 | Jun 4 | May 31 | May 25 | May 20 | May 16 | May 11 | May 4 |
| 28°F | May 30 | May 19 | May 13 | May 8 | May 4 | May 1 | Apr 27 | Apr 22 | Apr 17 |
| 24°F | May 4 | Apr 28 | Apr 24 | Apr 19 | Apr 15 | Apr 11 | Apr 8 | Apr 4 | Mar 30 |
| 20°F | Apr 16 | Apr 9 | Apr 5 | Apr 2 | Mar 30 | Mar 26 | Mar 21 | Mar 16 | Mar 10 |
| 16°F | Apr 3 | Mar 28 | Mar 22 | Mar 17 | Mar 14 | Mar 10 | Mar 7 | Mar 3 | Feb 26 |
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 1 | Sep 5 | Sep 9 | Sep 13 | Sep 15 | Sep 17 | Sep 20 | Sep 23 | Sep 28 |
| 32°F | Sep 12 | Sep 17 | Sep 21 | Sep 24 | Sep 26 | Sep 29 | Oct 1 | Oct 5 | Oct 12 |
| 28°F | Sep 23 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 18 | Oct 23 |
| 24°F | Oct 4 | Oct 8 | Oct 13 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Oct 31 | Nov 5 |
| 20°F | Oct 17 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
| 16°F | Oct 26 | Nov 2 | Nov 6 | Nov 9 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 27 |
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 | 119 | 110 | 105 | 99 | 95 | 91 | 86 | 81 | 72 |
| 32°F | 148 | 140 | 134 | 129 | 123 | 118 | 112 | 106 | 98 |
| 28°F | 180 | 172 | 167 | 161 | 156 | 151 | 146 | 138 | 127 |
| 24°F | 209 | 202 | 197 | 192 | 188 | 182 | 176 | 171 | 162 |
| 20°F | 240 | 231 | 225 | 220 | 216 | 212 | 206 | 200 | 194 |
| 16°F | 265 | 258 | 252 | 247 | 242 | 237 | 231 | 224 | 216 |
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
- 7,193
- Cooling degree days, base 65°F
- 319
- Growing degree days, base 40°F
- 3,930
- Growing degree days, base 45°F
- 2,898
- Growing degree days, base 50°F
- 2,026
- Growing degree days, base 55°F
- 1,306
- Growing degree days, base 60°F
- 734
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,268 | 0 | 0 |
| February | 1,050 | 0 | 0 |
| March | 857 | 0 | 5 |
| April | 619 | 0 | 26 |
| May | 387 | 3 | 129 |
| June | 141 | 28 | 342 |
| July | 11 | 152 | 606 |
| August | 17 | 123 | 572 |
| September | 194 | 13 | 279 |
| October | 541 | 0 | 63 |
| November | 876 | 0 | 5 |
| December | 1,232 | 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 1.6 km from Liberty. 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 USC00422389 (Eden-Liberty). Public domain.