Boothville Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Boothville Asos. 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 January 23 and the first fall freeze around January 9, a growing season of about 357 days.
- Median at 36°F
- last February 6, first January 4
- Median at 32°F
- last January 23, first January 9
- Median at 28°F
- last January 16, first January 13
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 | Mar 5 | Feb 26 | Feb 19 | Feb 12 | Feb 6 | Feb 1 | Jan 26 | Jan 18 | Jan 8 |
| 32°F | Feb 25 | Feb 12 | Feb 3 | Jan 30 | Jan 23 | Jan 16 | Jan 11 | Jan 6 | Dec 28 |
| 28°F | Feb 12 | Feb 3 | Jan 28 | Jan 22 | Jan 16 | Jan 12 | Jan 8 | Jan 4 | Dec 31 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 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 | Dec 7 | Dec 17 | Dec 24 | Dec 31 | Jan 4 | Jan 8 | Jan 12 | Jan 19 | Feb 1 |
| 32°F | Dec 18 | Dec 27 | Jan 1 | Jan 6 | Jan 9 | Jan 15 | Jan 20 | Jan 29 | Feb 5 |
| 28°F | Dec 28 | Jan 1 | Jan 5 | Jan 9 | Jan 13 | Jan 18 | Jan 24 | Jan 31 | Feb 4 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 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 | 360 | 347 | 337 | 331 | 325 | 317 | 309 | 303 | 293 |
| 32°F | 365 | 365 | 365 | 365 | 357 | 350 | 340 | 332 | 318 |
| 28°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 360 | 343 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 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
- 91% of years
- 32°F or colder
- 60% of years
- 28°F or colder
- 23% of years
- 24°F or colder
- 6% 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
- 1,072
- Cooling degree days, base 65°F
- 3,048
- Growing degree days, base 40°F
- 11,106
- Growing degree days, base 45°F
- 9,302
- Growing degree days, base 50°F
- 7,545
- Growing degree days, base 55°F
- 5,888
- Growing degree days, base 60°F
- 4,378
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 329 | 11 | 195 |
| February | 226 | 18 | 231 |
| March | 124 | 49 | 393 |
| April | 25 | 142 | 567 |
| May | 1 | 342 | 806 |
| June | 0 | 500 | 949 |
| July | 0 | 564 | 1,029 |
| August | 0 | 570 | 1,035 |
| September | 0 | 479 | 928 |
| October | 12 | 273 | 725 |
| November | 103 | 73 | 422 |
| December | 253 | 27 | 263 |
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 1.7 km from Boothville. 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 USW00012884 (Boothville Asos). Public domain.