Exeter Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Lindsay. 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 February 20 and the first fall freeze around November 30, a growing season of about 284 days.
- Median at 36°F
- last March 31, first November 15
- Median at 32°F
- last February 20, first November 30
- Median at 28°F
- last January 20, first December 14
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 26 | Apr 16 | Apr 9 | Apr 4 | Mar 31 | Mar 22 | Mar 13 | Mar 2 | Feb 24 |
| 32°F | Mar 26 | Mar 11 | Mar 2 | Feb 26 | Feb 20 | Feb 13 | Feb 6 | Jan 31 | Jan 20 |
| 28°F | Feb 18 | Feb 8 | Feb 2 | Jan 29 | Jan 20 | Jan 14 | Jan 5 | Dec 31 | Dec 25 |
| 24°F | Jan 31 | Jan 19 | Jan 11 | Jan 4 | Dec 31 | Dec 29 | Dec 27 | Dec 23 | Dec 15 |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
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 27 | Nov 1 | Nov 6 | Nov 11 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 30 |
| 32°F | Nov 15 | Nov 21 | Nov 24 | Nov 27 | Nov 30 | Dec 2 | Dec 5 | Dec 10 | Dec 21 |
| 28°F | Nov 28 | Dec 2 | Dec 5 | Dec 9 | Dec 14 | Dec 20 | Dec 28 | Jan 5 | Jan 17 |
| 24°F | Dec 8 | Dec 13 | Dec 16 | Dec 21 | Dec 25 | Dec 29 | Jan 1 | Jan 7 | Jan 16 |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
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 | 267 | 255 | 244 | 236 | 230 | 223 | 215 | 207 | 195 |
| 32°F | 320 | 308 | 299 | 291 | 284 | 276 | 268 | 259 | 243 |
| 28°F | 365 | 356 | 346 | 339 | 334 | 329 | 322 | 313 | 302 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 361 | 352 | 342 |
| 20°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
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
- 86% of years
- 24°F or colder
- 35% of years
- 20°F or colder
- 3% of years
- 16°F or colder
- 0% 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
- 2,448
- Cooling degree days, base 65°F
- 1,699
- Growing degree days, base 40°F
- 8,388
- Growing degree days, base 45°F
- 6,645
- Growing degree days, base 50°F
- 5,071
- Growing degree days, base 55°F
- 3,722
- Growing degree days, base 60°F
- 2,606
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 556 | 0 | 29 |
| February | 384 | 0 | 81 |
| March | 276 | 4 | 209 |
| April | 159 | 28 | 322 |
| May | 55 | 132 | 543 |
| June | 7 | 286 | 729 |
| July | 0 | 476 | 941 |
| August | 0 | 433 | 897 |
| September | 6 | 273 | 717 |
| October | 92 | 65 | 439 |
| November | 345 | 2 | 138 |
| December | 569 | 0 | 27 |
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 13 km from Exeter. 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 USC00044957 (Lindsay). Public domain.