Hidden Meadows Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Valley Ctr 1N. 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 19 and the first fall freeze around December 1, a growing season of about 281 days.
- Median at 36°F
- last April 2, first November 13
- Median at 32°F
- last February 19, first December 1
- Median at 28°F
- last January 8, first December 17
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 22 | Apr 16 | Apr 11 | Apr 6 | Apr 2 | Mar 27 | Mar 19 | Mar 12 | Mar 1 |
| 32°F | Mar 31 | Mar 16 | Mar 4 | Feb 26 | Feb 19 | Feb 12 | Feb 4 | Jan 25 | Jan 10 |
| 28°F | Feb 14 | Feb 3 | Jan 25 | Jan 16 | Jan 8 | Jan 2 | Dec 30 | Dec 22 | Dec 13 |
| 24°F | Jan 28 | Jan 15 | Jan 7 | Jan 1 | Dec 30 | Dec 26 | Dec 22 | Dec 16 | Dec 10 |
| 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 22 | Oct 31 | Nov 5 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Dec 1 |
| 32°F | Nov 11 | Nov 18 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 20 |
| 28°F | Nov 28 | Dec 4 | Dec 9 | Dec 13 | Dec 17 | Dec 21 | Dec 27 | Dec 31 | Jan 12 |
| 24°F | Dec 9 | Dec 13 | Dec 20 | Dec 23 | Dec 26 | Dec 30 | Jan 2 | Jan 7 | Jan 21 |
| 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 | 256 | 247 | 239 | 232 | 225 | 218 | 212 | 206 | 197 |
| 32°F | 321 | 310 | 300 | 290 | 281 | 273 | 263 | 253 | 240 |
| 28°F | 365 | 360 | 353 | 346 | 340 | 334 | 326 | 317 | 303 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 360 | 347 |
| 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
- 85% of years
- 24°F or colder
- 26% of years
- 20°F or colder
- 1% 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
- 1,955
- Cooling degree days, base 65°F
- 1,150
- Growing degree days, base 40°F
- 8,320
- Growing degree days, base 45°F
- 6,504
- Growing degree days, base 50°F
- 4,764
- Growing degree days, base 55°F
- 3,243
- Growing degree days, base 60°F
- 2,045
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 378 | 0 | 108 |
| February | 325 | 1 | 125 |
| March | 272 | 3 | 203 |
| April | 182 | 8 | 277 |
| May | 98 | 40 | 408 |
| June | 15 | 129 | 564 |
| July | 0 | 296 | 761 |
| August | 0 | 338 | 803 |
| September | 6 | 262 | 706 |
| October | 60 | 68 | 473 |
| November | 213 | 6 | 248 |
| December | 406 | 0 | 88 |
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 6.9 km from Hidden Meadows. 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 USC00049226 (Valley Ctr 1N). Public domain.