Wolf Point Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Wolf Pt. 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 8 and the first fall freeze around September 28, a growing season of about 143 days.
- Median at 36°F
- last May 18, first September 20
- Median at 32°F
- last May 8, first September 28
- Median at 28°F
- last April 29, first October 7
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 30 | May 26 | May 23 | May 21 | May 18 | May 16 | May 13 | May 11 | May 7 |
| 32°F | May 20 | May 17 | May 13 | May 11 | May 8 | May 5 | May 3 | Apr 30 | Apr 25 |
| 28°F | May 11 | May 7 | May 3 | May 1 | Apr 29 | Apr 26 | Apr 22 | Apr 19 | Apr 14 |
| 24°F | May 2 | Apr 27 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 10 | Apr 6 | Apr 1 |
| 20°F | Apr 22 | Apr 15 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 27 | Mar 18 |
| 16°F | Apr 13 | Apr 7 | Apr 4 | Apr 1 | Mar 29 | Mar 24 | Mar 20 | Mar 15 | Mar 10 |
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 7 | Sep 12 | Sep 15 | Sep 18 | Sep 20 | Sep 22 | Sep 25 | Sep 27 | Oct 1 |
| 32°F | Sep 15 | Sep 20 | Sep 23 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 11 |
| 28°F | Sep 21 | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 15 | Oct 18 | Oct 23 |
| 24°F | Sep 29 | Oct 6 | Oct 11 | Oct 15 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Nov 1 |
| 20°F | Oct 10 | Oct 16 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 11 |
| 16°F | Oct 18 | Oct 25 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 15 | Nov 20 |
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 | 141 | 135 | 131 | 127 | 124 | 120 | 116 | 112 | 105 |
| 32°F | 161 | 155 | 151 | 148 | 143 | 140 | 135 | 130 | 123 |
| 28°F | 182 | 175 | 170 | 166 | 162 | 158 | 153 | 148 | 141 |
| 24°F | 205 | 197 | 192 | 188 | 183 | 179 | 174 | 170 | 159 |
| 20°F | 226 | 218 | 213 | 208 | 204 | 200 | 195 | 188 | 180 |
| 16°F | 245 | 236 | 230 | 225 | 220 | 216 | 211 | 205 | 197 |
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
- 7,806
- Cooling degree days, base 65°F
- 667
- Growing degree days, base 40°F
- 4,568
- Growing degree days, base 45°F
- 3,531
- Growing degree days, base 50°F
- 2,623
- Growing degree days, base 55°F
- 1,833
- Growing degree days, base 60°F
- 1,178
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,527 | 0 | 0 |
| February | 1,240 | 0 | 1 |
| March | 978 | 0 | 9 |
| April | 559 | 1 | 64 |
| May | 274 | 20 | 242 |
| June | 72 | 90 | 469 |
| July | 11 | 258 | 713 |
| August | 21 | 238 | 682 |
| September | 173 | 56 | 349 |
| October | 560 | 5 | 88 |
| November | 986 | 0 | 7 |
| December | 1,407 | 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 1.1 km from Wolf Point. 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 USC00249103 (Wolf Pt). Public domain.