Oak City Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Oak City. 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 13, a growing season of about 162 days.
- Median at 36°F
- last May 16, first October 4
- Median at 32°F
- last May 2, first October 13
- Median at 28°F
- last April 20, first October 24
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 3 | May 30 | May 25 | May 20 | May 16 | May 13 | May 10 | May 5 | Apr 30 |
| 32°F | May 21 | May 14 | May 10 | May 5 | May 2 | Apr 30 | Apr 26 | Apr 23 | Apr 18 |
| 28°F | May 9 | May 1 | Apr 27 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 10 | Apr 5 |
| 24°F | Apr 23 | Apr 17 | Apr 12 | Apr 8 | Apr 4 | Mar 31 | Mar 25 | Mar 18 | Mar 10 |
| 20°F | Apr 5 | Mar 30 | Mar 24 | Mar 16 | Mar 11 | Mar 7 | Mar 3 | Feb 28 | Feb 20 |
| 16°F | Mar 12 | Mar 6 | Mar 2 | Feb 28 | Feb 24 | Feb 21 | Feb 16 | Feb 10 | Feb 3 |
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 21 | Sep 27 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 13 | Oct 19 |
| 32°F | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 16 | Oct 20 | Oct 24 | Oct 30 |
| 28°F | Oct 7 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 3 | Nov 8 |
| 24°F | Oct 18 | Oct 23 | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 18 |
| 20°F | Oct 28 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 24 | Nov 29 |
| 16°F | Nov 6 | Nov 11 | Nov 16 | Nov 19 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 8 |
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 | 161 | 153 | 148 | 143 | 138 | 133 | 128 | 121 | 114 |
| 32°F | 183 | 176 | 171 | 166 | 162 | 158 | 153 | 147 | 139 |
| 28°F | 210 | 200 | 194 | 190 | 186 | 181 | 176 | 170 | 161 |
| 24°F | 239 | 230 | 223 | 218 | 213 | 208 | 202 | 195 | 188 |
| 20°F | 271 | 261 | 256 | 250 | 244 | 238 | 232 | 226 | 215 |
| 16°F | 298 | 288 | 283 | 277 | 271 | 266 | 260 | 252 | 244 |
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
- 5,782
- Cooling degree days, base 65°F
- 1,185
- Growing degree days, base 40°F
- 5,649
- Growing degree days, base 45°F
- 4,462
- Growing degree days, base 50°F
- 3,440
- Growing degree days, base 55°F
- 2,562
- Growing degree days, base 60°F
- 1,815
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,105 | 0 | 1 |
| February | 867 | 0 | 2 |
| March | 690 | 0 | 25 |
| April | 493 | 3 | 87 |
| May | 229 | 42 | 301 |
| June | 48 | 208 | 611 |
| July | 1 | 428 | 892 |
| August | 3 | 364 | 826 |
| September | 78 | 130 | 509 |
| October | 393 | 11 | 164 |
| November | 770 | 0 | 20 |
| December | 1,106 | 0 | 1 |
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 3.1 km from Oak City. 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 USC00426357 (Oak City). Public domain.