Redwood Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Gouverneur 3 Nw. 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 May 14 and the first fall freeze around September 26, a growing season of about 134 days.
- Median at 36°F
- last May 27, first September 16
- Median at 32°F
- last May 14, first September 26
- Median at 28°F
- last May 2, first October 8
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 | Jun 10 | Jun 5 | Jun 1 | May 30 | May 27 | May 24 | May 21 | May 16 | May 11 |
| 32°F | May 30 | May 24 | May 20 | May 17 | May 14 | May 11 | May 8 | May 4 | Apr 30 |
| 28°F | May 17 | May 12 | May 8 | May 5 | May 2 | Apr 30 | Apr 28 | Apr 24 | Apr 21 |
| 24°F | May 7 | May 1 | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 16 | Apr 13 | Apr 8 |
| 20°F | Apr 22 | Apr 18 | Apr 14 | Apr 11 | Apr 8 | Apr 6 | Apr 4 | Apr 1 | Mar 30 |
| 16°F | Apr 13 | Apr 8 | Apr 5 | Apr 3 | Apr 2 | Mar 31 | Mar 29 | Mar 24 | Mar 19 |
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 2 | Sep 6 | Sep 10 | Sep 13 | Sep 16 | Sep 19 | Sep 23 | Sep 26 | Sep 30 |
| 32°F | Sep 12 | Sep 16 | Sep 20 | Sep 24 | Sep 26 | Sep 30 | Oct 2 | Oct 6 | Oct 12 |
| 28°F | Sep 23 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 16 | Oct 20 | Oct 27 |
| 24°F | Oct 3 | Oct 9 | Oct 15 | Oct 18 | Oct 22 | Oct 25 | Oct 28 | Nov 2 | Nov 6 |
| 20°F | Oct 18 | Oct 24 | Oct 28 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 19 |
| 16°F | Oct 30 | Nov 4 | Nov 7 | Nov 11 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 28 |
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 | 131 | 124 | 119 | 115 | 111 | 107 | 103 | 97 | 91 |
| 32°F | 154 | 147 | 141 | 137 | 134 | 129 | 125 | 121 | 113 |
| 28°F | 178 | 170 | 164 | 161 | 157 | 152 | 148 | 143 | 136 |
| 24°F | 203 | 197 | 191 | 186 | 181 | 176 | 171 | 165 | 158 |
| 20°F | 226 | 220 | 215 | 210 | 206 | 202 | 197 | 192 | 184 |
| 16°F | 246 | 238 | 233 | 228 | 225 | 220 | 217 | 212 | 205 |
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
- 8,153
- Cooling degree days, base 65°F
- 342
- Growing degree days, base 40°F
- 3,915
- Growing degree days, base 45°F
- 2,924
- Growing degree days, base 50°F
- 2,073
- Growing degree days, base 55°F
- 1,350
- Growing degree days, base 60°F
- 763
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,525 | 0 | 1 |
| February | 1,330 | 0 | 0 |
| March | 1,155 | 0 | 4 |
| April | 685 | 1 | 34 |
| May | 351 | 12 | 178 |
| June | 104 | 64 | 413 |
| July | 29 | 130 | 566 |
| August | 49 | 101 | 518 |
| September | 217 | 32 | 282 |
| October | 560 | 2 | 68 |
| November | 873 | 0 | 10 |
| December | 1,277 | 0 | 1 |
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 23.7 km from Redwood. 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 USC00303346 (Gouverneur 3 Nw). Public domain.