Paul Smiths Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Saranac Rgnl AP. 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 June 2 and the first fall freeze around September 9, a growing season of about 97 days.
- Median at 32°F
- last June 2, first September 9
- Median at 28°F
- last May 21, first September 23
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 | – | – | – | – | – | – | – | – | – |
| 32°F | Jun 19 | Jun 13 | Jun 9 | Jun 5 | Jun 2 | May 31 | May 28 | May 26 | May 20 |
| 28°F | Jun 4 | May 31 | May 27 | May 24 | May 21 | May 19 | May 16 | May 13 | May 7 |
| 24°F | May 24 | May 18 | May 15 | May 12 | May 9 | May 6 | May 2 | Apr 29 | Apr 25 |
| 20°F | May 12 | May 7 | May 3 | May 1 | Apr 28 | Apr 24 | Apr 22 | Apr 18 | Apr 12 |
| 16°F | May 1 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Apr 2 |
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 | – | – | – | – | – | – | – | – | – |
| 32°F | Aug 26 | Sep 1 | Sep 3 | Sep 6 | Sep 9 | Sep 12 | Sep 16 | Sep 19 | Sep 24 |
| 28°F | Sep 7 | Sep 13 | Sep 17 | Sep 21 | Sep 23 | Sep 26 | Sep 28 | Oct 2 | Oct 7 |
| 24°F | Sep 19 | Sep 25 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 14 | Oct 18 | Oct 25 |
| 20°F | Oct 4 | Oct 10 | Oct 16 | Oct 19 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 7 |
| 16°F | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 2 | Nov 5 | Nov 7 | Nov 11 | Nov 16 |
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 | 90 | 81 | 75 | 69 | 63 | 58 | 51 | 45 | 36 |
| 32°F | 118 | 110 | 104 | 100 | 97 | 93 | 89 | 82 | 72 |
| 28°F | 144 | 135 | 131 | 126 | 123 | 119 | 115 | 109 | 103 |
| 24°F | 169 | 163 | 158 | 153 | 149 | 145 | 141 | 136 | 127 |
| 20°F | 198 | 191 | 184 | 180 | 176 | 171 | 167 | 161 | 153 |
| 16°F | 219 | 213 | 208 | 204 | 200 | 196 | 192 | 187 | 180 |
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
- 9,302
- Cooling degree days, base 65°F
- 120
- Growing degree days, base 40°F
- 3,056
- Growing degree days, base 45°F
- 2,171
- Growing degree days, base 50°F
- 1,418
- Growing degree days, base 55°F
- 811
- Growing degree days, base 60°F
- 374
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,593 | 0 | 0 |
| February | 1,393 | 0 | 0 |
| March | 1,269 | 0 | 2 |
| April | 806 | 0 | 17 |
| May | 455 | 4 | 111 |
| June | 195 | 25 | 288 |
| July | 91 | 50 | 423 |
| August | 135 | 32 | 364 |
| September | 326 | 9 | 177 |
| October | 673 | 0 | 34 |
| November | 993 | 0 | 2 |
| December | 1,373 | 0 | 0 |
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 7 km from Paul Smiths. 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 USW00094740 (Saranac Rgnl AP). Public domain.