Cove Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Union. 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 11 and the first fall freeze around September 26, a growing season of about 136 days.
- Median at 36°F
- last June 2, first September 10
- Median at 32°F
- last May 11, first September 26
- Median at 28°F
- last April 24, 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 23 | Jun 15 | Jun 10 | Jun 6 | Jun 2 | May 30 | May 26 | May 21 | May 14 |
| 32°F | May 31 | May 24 | May 19 | May 15 | May 11 | May 8 | May 4 | May 1 | Apr 26 |
| 28°F | May 10 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 7 |
| 24°F | Apr 22 | Apr 15 | Apr 10 | Apr 6 | Apr 3 | Mar 30 | Mar 26 | Mar 20 | Mar 12 |
| 20°F | Apr 3 | Mar 26 | Mar 19 | Mar 14 | Mar 10 | Mar 6 | Mar 2 | Feb 25 | Feb 16 |
| 16°F | Mar 8 | Mar 3 | Feb 28 | Feb 24 | Feb 20 | Feb 15 | Feb 10 | Feb 4 | Jan 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 29 | Sep 2 | Sep 5 | Sep 8 | Sep 10 | Sep 14 | Sep 17 | Sep 21 | Sep 26 |
| 32°F | Sep 9 | Sep 15 | Sep 20 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 5 | Oct 10 |
| 28°F | Sep 23 | Sep 29 | Oct 2 | Oct 5 | Oct 7 | Oct 11 | Oct 14 | Oct 18 | Oct 23 |
| 24°F | Oct 3 | Oct 8 | Oct 14 | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 2 | Nov 11 |
| 20°F | Oct 16 | Oct 22 | Oct 27 | Nov 1 | Nov 5 | Nov 10 | Nov 16 | Nov 24 | Nov 30 |
| 16°F | Oct 27 | Nov 2 | Nov 10 | Nov 17 | Nov 23 | Nov 28 | Dec 2 | Dec 9 | Dec 17 |
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 | 124 | 117 | 111 | 105 | 101 | 96 | 90 | 85 | 76 |
| 32°F | 158 | 151 | 145 | 140 | 136 | 131 | 126 | 121 | 112 |
| 28°F | 190 | 182 | 177 | 172 | 166 | 162 | 157 | 152 | 144 |
| 24°F | 231 | 220 | 213 | 207 | 202 | 197 | 191 | 184 | 174 |
| 20°F | 274 | 262 | 254 | 247 | 241 | 235 | 229 | 222 | 210 |
| 16°F | 317 | 301 | 292 | 285 | 277 | 270 | 264 | 256 | 245 |
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
- 6,190
- Cooling degree days, base 65°F
- 375
- Growing degree days, base 40°F
- 4,160
- Growing degree days, base 45°F
- 3,015
- Growing degree days, base 50°F
- 2,086
- Growing degree days, base 55°F
- 1,342
- Growing degree days, base 60°F
- 772
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,009 | 0 | 0 |
| February | 819 | 0 | 1 |
| March | 725 | 0 | 11 |
| April | 551 | 0 | 44 |
| May | 336 | 9 | 179 |
| June | 171 | 36 | 320 |
| July | 44 | 148 | 569 |
| August | 42 | 149 | 572 |
| September | 186 | 32 | 306 |
| October | 511 | 1 | 74 |
| November | 774 | 0 | 10 |
| December | 1,021 | 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 11.8 km from Cove. 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 USC00358746 (Union). Public domain.