North Hudson Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Stillwater 1 Se. 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 April 22 and the first fall freeze around October 19, a growing season of about 178 days.
- Median at 36°F
- last May 2, first October 8
- Median at 32°F
- last April 22, first October 19
- Median at 28°F
- last April 12, first October 30
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 | May 17 | May 11 | May 7 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 23 | Apr 19 |
| 32°F | May 6 | May 1 | Apr 28 | Apr 25 | Apr 22 | Apr 19 | Apr 15 | Apr 12 | Apr 7 |
| 28°F | Apr 27 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Mar 31 |
| 24°F | Apr 18 | Apr 12 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 30 | Mar 25 | Mar 19 |
| 20°F | Apr 9 | Apr 4 | Apr 2 | Mar 31 | Mar 28 | Mar 24 | Mar 20 | Mar 16 | Mar 11 |
| 16°F | Apr 3 | Mar 31 | Mar 27 | Mar 23 | Mar 20 | Mar 17 | Mar 14 | Mar 10 | Mar 6 |
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 | Sep 25 | Sep 30 | Oct 3 | Oct 5 | Oct 8 | Oct 10 | Oct 14 | Oct 18 | Oct 23 |
| 32°F | Oct 3 | Oct 8 | Oct 13 | Oct 17 | Oct 19 | Oct 22 | Oct 26 | Oct 30 | Nov 3 |
| 28°F | Oct 15 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 11 |
| 24°F | Oct 26 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 8 | Nov 11 | Nov 14 | Nov 19 |
| 20°F | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 16 | Nov 19 | Nov 22 | Nov 27 |
| 16°F | Nov 7 | Nov 12 | Nov 15 | Nov 18 | Nov 20 | Nov 23 | Nov 26 | Nov 29 | Dec 3 |
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 | 178 | 170 | 166 | 161 | 158 | 154 | 149 | 144 | 137 |
| 32°F | 200 | 193 | 187 | 182 | 178 | 173 | 169 | 164 | 157 |
| 28°F | 218 | 211 | 207 | 203 | 199 | 195 | 190 | 186 | 180 |
| 24°F | 234 | 228 | 223 | 218 | 215 | 211 | 207 | 203 | 196 |
| 20°F | 249 | 244 | 239 | 235 | 231 | 226 | 223 | 218 | 211 |
| 16°F | 264 | 257 | 252 | 248 | 244 | 240 | 236 | 231 | 223 |
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
- 6,928
- Cooling degree days, base 65°F
- 927
- Growing degree days, base 40°F
- 5,256
- Growing degree days, base 45°F
- 4,172
- Growing degree days, base 50°F
- 3,188
- Growing degree days, base 55°F
- 2,317
- Growing degree days, base 60°F
- 1,557
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,460 | 0 | 0 |
| February | 1,183 | 0 | 0 |
| March | 939 | 0 | 9 |
| April | 495 | 7 | 97 |
| May | 172 | 55 | 358 |
| June | 26 | 191 | 615 |
| July | 3 | 305 | 767 |
| August | 6 | 257 | 716 |
| September | 93 | 103 | 464 |
| October | 428 | 11 | 144 |
| November | 850 | 0 | 17 |
| December | 1,274 | 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 6.3 km from North Hudson. 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 USC00218037 (Stillwater 1 Se). Public domain.