Elma Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for New Hampton. 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 2 and the first fall freeze around October 5, a growing season of about 155 days.
- Median at 36°F
- last May 10, first September 28
- Median at 32°F
- last May 2, first October 5
- Median at 28°F
- last April 20, first October 15
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 23 | May 19 | May 15 | May 12 | May 10 | May 8 | May 5 | May 2 | Apr 29 |
| 32°F | May 14 | May 9 | May 6 | May 4 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 17 |
| 28°F | May 5 | May 1 | Apr 28 | Apr 23 | Apr 20 | Apr 17 | Apr 13 | Apr 10 | Apr 5 |
| 24°F | Apr 28 | Apr 21 | Apr 17 | Apr 13 | Apr 10 | Apr 7 | Apr 4 | Apr 2 | Mar 29 |
| 20°F | Apr 18 | Apr 11 | Apr 7 | Apr 4 | Apr 2 | Mar 31 | Mar 28 | Mar 23 | Mar 16 |
| 16°F | Apr 8 | Apr 3 | Mar 31 | Mar 28 | Mar 24 | Mar 21 | Mar 17 | Mar 14 | Mar 8 |
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 16 | Sep 20 | Sep 23 | Sep 25 | Sep 28 | Sep 30 | Oct 2 | Oct 5 | Oct 9 |
| 32°F | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 |
| 28°F | Oct 1 | Oct 6 | Oct 10 | Oct 12 | Oct 15 | Oct 17 | Oct 20 | Oct 23 | Oct 27 |
| 24°F | Oct 11 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 6 |
| 20°F | Oct 21 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 18 |
| 16°F | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | 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 | 155 | 149 | 146 | 143 | 139 | 136 | 132 | 127 | 121 |
| 32°F | 173 | 167 | 163 | 159 | 155 | 152 | 148 | 144 | 137 |
| 28°F | 194 | 187 | 183 | 179 | 175 | 171 | 167 | 162 | 155 |
| 24°F | 215 | 209 | 204 | 200 | 196 | 192 | 188 | 183 | 176 |
| 20°F | 235 | 228 | 223 | 218 | 214 | 210 | 206 | 201 | 194 |
| 16°F | 251 | 244 | 240 | 235 | 231 | 227 | 223 | 218 | 211 |
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
- 7,872
- Cooling degree days, base 65°F
- 521
- Growing degree days, base 40°F
- 4,419
- Growing degree days, base 45°F
- 3,402
- Growing degree days, base 50°F
- 2,499
- Growing degree days, base 55°F
- 1,711
- Growing degree days, base 60°F
- 1,045
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,569 | 0 | 0 |
| February | 1,294 | 0 | 0 |
| March | 1,033 | 0 | 11 |
| April | 596 | 2 | 57 |
| May | 268 | 27 | 255 |
| June | 48 | 121 | 524 |
| July | 13 | 184 | 635 |
| August | 28 | 133 | 570 |
| September | 170 | 48 | 341 |
| October | 532 | 5 | 96 |
| November | 951 | 0 | 8 |
| December | 1,372 | 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 24.6 km from Elma. 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 USC00135952 (New Hampton). Public domain.