Ward County Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Minot Exp Stn. 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 13 and the first fall freeze around September 27, a growing season of about 136 days.
- Median at 36°F
- last May 22, first September 20
- Median at 32°F
- last May 13, first September 27
- Median at 28°F
- last May 3, first October 5
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 3 | May 30 | May 27 | May 24 | May 22 | May 19 | May 17 | May 13 | May 10 |
| 32°F | May 26 | May 21 | May 18 | May 15 | May 13 | May 10 | May 7 | May 4 | May 1 |
| 28°F | May 16 | May 12 | May 9 | May 6 | May 3 | May 1 | Apr 29 | Apr 23 | Apr 18 |
| 24°F | May 8 | May 3 | Apr 30 | Apr 27 | Apr 23 | Apr 20 | Apr 17 | Apr 13 | Apr 9 |
| 20°F | Apr 30 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 1 |
| 16°F | Apr 20 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 22 |
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 5 | Sep 11 | Sep 14 | Sep 17 | Sep 20 | Sep 22 | Sep 24 | Sep 27 | Oct 1 |
| 32°F | Sep 14 | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 29 | Oct 2 | Oct 5 | Oct 9 |
| 28°F | Sep 22 | Sep 26 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 |
| 24°F | Oct 1 | Oct 4 | Oct 8 | Oct 12 | Oct 14 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
| 20°F | Oct 8 | Oct 13 | Oct 17 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 16°F | Oct 15 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 9 | Nov 14 |
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 | 136 | 130 | 126 | 122 | 119 | 116 | 111 | 107 | 101 |
| 32°F | 153 | 147 | 143 | 139 | 136 | 132 | 128 | 124 | 118 |
| 28°F | 173 | 166 | 162 | 158 | 154 | 150 | 147 | 142 | 136 |
| 24°F | 194 | 187 | 182 | 177 | 173 | 169 | 165 | 159 | 152 |
| 20°F | 210 | 204 | 199 | 194 | 190 | 186 | 182 | 176 | 170 |
| 16°F | 225 | 218 | 213 | 209 | 205 | 200 | 196 | 192 | 184 |
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
- 9,388
- Cooling degree days, base 65°F
- 344
- Growing degree days, base 40°F
- 3,684
- Growing degree days, base 45°F
- 2,776
- Growing degree days, base 50°F
- 1,978
- Growing degree days, base 55°F
- 1,298
- Growing degree days, base 60°F
- 746
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,717 | 0 | 0 |
| February | 1,448 | 0 | 0 |
| March | 1,234 | 0 | 1 |
| April | 752 | 1 | 27 |
| May | 377 | 11 | 174 |
| June | 113 | 56 | 396 |
| July | 36 | 132 | 561 |
| August | 58 | 118 | 526 |
| September | 263 | 26 | 246 |
| October | 700 | 1 | 44 |
| November | 1,137 | 0 | 3 |
| December | 1,555 | 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 18.8 km from Ward County. 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 USC00325993 (Minot Exp Stn). Public domain.