North Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for N 5NE. 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 March 26 and the first fall freeze around November 6, a growing season of about 227 days.
- Median at 36°F
- last April 5, first October 29
- Median at 32°F
- last March 26, first November 6
- Median at 28°F
- last March 13, first November 16
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 | Apr 20 | Apr 16 | Apr 11 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 27 | Mar 20 |
| 32°F | Apr 11 | Apr 5 | Apr 2 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 8 |
| 28°F | Mar 31 | Mar 25 | Mar 20 | Mar 16 | Mar 13 | Mar 9 | Mar 5 | Feb 28 | Feb 22 |
| 24°F | Mar 19 | Mar 14 | Mar 7 | Mar 2 | Feb 26 | Feb 21 | Feb 14 | Feb 8 | Jan 31 |
| 20°F | Mar 7 | Feb 28 | Feb 20 | Feb 11 | Feb 6 | Feb 1 | Jan 29 | Jan 19 | Jan 5 |
| 16°F | Feb 27 | Feb 14 | Feb 7 | Jan 31 | Jan 28 | Jan 22 | Jan 15 | Jan 8 | Dec 31 |
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 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 10 |
| 32°F | Oct 25 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 20 |
| 28°F | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 24 | Nov 29 | Dec 8 |
| 24°F | Nov 11 | Nov 17 | Nov 22 | Nov 28 | Dec 3 | Dec 9 | Dec 20 | Dec 29 | Jan 9 |
| 20°F | Nov 26 | Dec 4 | Dec 16 | Dec 25 | Jan 1 | Jan 6 | Jan 12 | Jan 19 | Feb 1 |
| 16°F | Dec 15 | Dec 28 | Jan 3 | Jan 8 | Jan 13 | Jan 17 | Jan 24 | Jan 31 | Feb 11 |
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 | 228 | 221 | 215 | 211 | 207 | 203 | 199 | 195 | 188 |
| 32°F | 250 | 242 | 236 | 231 | 227 | 222 | 217 | 211 | 204 |
| 28°F | 279 | 269 | 261 | 255 | 249 | 244 | 238 | 232 | 224 |
| 24°F | 321 | 308 | 297 | 290 | 283 | 276 | 269 | 261 | 249 |
| 20°F | 362 | 346 | 335 | 328 | 319 | 311 | 302 | 293 | 280 |
| 16°F | 365 | 365 | 365 | 364 | 354 | 344 | 335 | 328 | 313 |
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
- 92% of years
- 16°F or colder
- 61% 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
- 2,514
- Cooling degree days, base 65°F
- 2,182
- Growing degree days, base 40°F
- 8,893
- Growing degree days, base 45°F
- 7,228
- Growing degree days, base 50°F
- 5,709
- Growing degree days, base 55°F
- 4,358
- Growing degree days, base 60°F
- 3,184
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 595 | 2 | 79 |
| February | 454 | 1 | 77 |
| March | 328 | 19 | 214 |
| April | 111 | 57 | 399 |
| May | 20 | 223 | 668 |
| June | 0 | 436 | 886 |
| July | 0 | 544 | 1,009 |
| August | 0 | 493 | 958 |
| September | 7 | 308 | 751 |
| October | 109 | 82 | 442 |
| November | 371 | 18 | 148 |
| December | 520 | 1 | 79 |
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 8.2 km from North. 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 USC00386299 (N 5NE). Public domain.