Baraga Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Herman. 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 31 and the first fall freeze around September 22, a growing season of about 115 days.
- Median at 32°F
- last May 31, first September 22
- Median at 28°F
- last May 14, first October 6
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 | – | – | – | – | – | – | – | – | – |
| 32°F | Jun 17 | Jun 10 | Jun 6 | Jun 2 | May 31 | May 27 | May 24 | May 18 | May 12 |
| 28°F | Jun 1 | May 26 | May 22 | May 18 | May 14 | May 11 | May 8 | May 4 | Apr 29 |
| 24°F | May 18 | May 13 | May 8 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 18 |
| 20°F | May 7 | May 2 | Apr 29 | Apr 26 | Apr 24 | Apr 21 | Apr 18 | Apr 14 | Apr 9 |
| 16°F | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 14 | Apr 12 | Apr 9 | Apr 5 | Apr 2 |
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 | – | – | – | – | – | – | – | – | – |
| 32°F | Sep 4 | Sep 10 | Sep 15 | Sep 18 | Sep 22 | Sep 26 | Sep 30 | Oct 4 | Oct 9 |
| 28°F | Sep 17 | Sep 23 | Sep 29 | Oct 2 | Oct 6 | Oct 9 | Oct 13 | Oct 18 | Oct 23 |
| 24°F | Sep 30 | Oct 7 | Oct 13 | Oct 17 | Oct 21 | Oct 25 | Oct 28 | Nov 1 | Nov 6 |
| 20°F | Oct 16 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 12 | Nov 17 |
| 16°F | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 25 |
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 | 110 | 102 | 96 | 90 | 84 | 78 | 72 | 61 | 50 |
| 32°F | 139 | 131 | 125 | 120 | 115 | 110 | 105 | 97 | 86 |
| 28°F | 167 | 159 | 153 | 147 | 143 | 138 | 133 | 127 | 119 |
| 24°F | 191 | 184 | 178 | 173 | 168 | 164 | 158 | 151 | 141 |
| 20°F | 210 | 203 | 199 | 194 | 189 | 185 | 180 | 175 | 168 |
| 16°F | 230 | 222 | 217 | 213 | 209 | 205 | 200 | 195 | 188 |
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
- 9,518
- Cooling degree days, base 65°F
- 187
- Growing degree days, base 40°F
- 3,140
- Growing degree days, base 45°F
- 2,285
- Growing degree days, base 50°F
- 1,543
- Growing degree days, base 55°F
- 932
- Growing degree days, base 60°F
- 475
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,615 | 0 | 0 |
| February | 1,400 | 0 | 0 |
| March | 1,268 | 0 | 3 |
| April | 854 | 0 | 16 |
| May | 454 | 12 | 139 |
| June | 187 | 37 | 312 |
| July | 97 | 71 | 439 |
| August | 130 | 49 | 386 |
| September | 311 | 16 | 201 |
| October | 693 | 1 | 44 |
| November | 1,071 | 0 | 3 |
| December | 1,438 | 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 15.2 km from Baraga. 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 USC00203744 (Herman). Public domain.