Gogebic County Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Bergland Dam. 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 26 and the first fall freeze around September 27, a growing season of about 123 days.
- Median at 36°F
- last June 4, first September 14
- Median at 32°F
- last May 26, first September 27
- Median at 28°F
- last May 12, 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 | Jun 18 | Jun 13 | Jun 9 | Jun 6 | Jun 4 | Jun 2 | May 31 | May 27 | May 23 |
| 32°F | Jun 8 | Jun 3 | May 31 | May 28 | May 26 | May 22 | May 19 | May 15 | May 9 |
| 28°F | May 28 | May 23 | May 19 | May 15 | May 12 | May 9 | May 6 | May 2 | Apr 28 |
| 24°F | May 17 | May 11 | May 7 | May 4 | May 1 | Apr 29 | Apr 26 | Apr 22 | Apr 16 |
| 20°F | May 6 | May 1 | Apr 28 | Apr 25 | Apr 22 | Apr 19 | Apr 15 | Apr 11 | Apr 6 |
| 16°F | Apr 27 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 10 | Apr 7 | Apr 4 | Apr 1 |
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 | Aug 28 | Sep 2 | Sep 6 | Sep 10 | Sep 14 | Sep 18 | Sep 21 | Sep 24 | Sep 30 |
| 32°F | Sep 10 | Sep 16 | Sep 21 | Sep 24 | Sep 27 | Oct 1 | Oct 2 | Oct 5 | Oct 9 |
| 28°F | Sep 22 | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 17 | Oct 23 |
| 24°F | Oct 3 | Oct 10 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 30 | Nov 2 | Nov 6 |
| 20°F | Oct 20 | Oct 25 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 17 |
| 16°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 22 | Nov 26 |
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 | 121 | 114 | 108 | 104 | 99 | 94 | 90 | 84 | 75 |
| 32°F | 142 | 136 | 131 | 127 | 123 | 119 | 115 | 110 | 103 |
| 28°F | 167 | 160 | 155 | 150 | 146 | 142 | 138 | 132 | 125 |
| 24°F | 192 | 185 | 179 | 175 | 171 | 166 | 162 | 157 | 148 |
| 20°F | 215 | 208 | 202 | 198 | 194 | 190 | 186 | 180 | 174 |
| 16°F | 231 | 225 | 221 | 218 | 213 | 210 | 205 | 201 | 193 |
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
- 9,422
- Cooling degree days, base 65°F
- 209
- Growing degree days, base 40°F
- 3,272
- Growing degree days, base 45°F
- 2,401
- Growing degree days, base 50°F
- 1,649
- Growing degree days, base 55°F
- 1,020
- Growing degree days, base 60°F
- 530
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,644 | 0 | 0 |
| February | 1,438 | 0 | 0 |
| March | 1,293 | 0 | 0 |
| April | 837 | 0 | 13 |
| May | 443 | 10 | 137 |
| June | 161 | 42 | 340 |
| July | 75 | 82 | 473 |
| August | 100 | 55 | 421 |
| September | 285 | 19 | 221 |
| October | 667 | 1 | 42 |
| November | 1,034 | 0 | 3 |
| December | 1,448 | 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 21.5 km from Gogebic 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 USC00200718 (Bergland Dam). Public domain.