Inkom Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Pocatello 2 Ne. 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 16 and the first fall freeze around October 2, a growing season of about 137 days.
- Median at 36°F
- last June 5, first September 21
- Median at 32°F
- last May 16, first October 2
- Median at 28°F
- last May 1, first October 13
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 14 | Jun 10 | Jun 7 | Jun 5 | Jun 2 | May 28 | May 22 | May 17 |
| 32°F | Jun 6 | May 31 | May 25 | May 20 | May 16 | May 12 | May 8 | May 4 | Apr 30 |
| 28°F | May 18 | May 12 | May 7 | May 3 | May 1 | Apr 28 | Apr 24 | Apr 20 | Apr 16 |
| 24°F | May 5 | Apr 30 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 6 | Apr 2 | Mar 25 |
| 20°F | Apr 19 | Apr 11 | Apr 5 | Mar 31 | Mar 28 | Mar 22 | Mar 17 | Mar 10 | Mar 3 |
| 16°F | Mar 30 | Mar 24 | Mar 17 | Mar 11 | Mar 8 | Mar 4 | Feb 28 | Feb 23 | Feb 16 |
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 10 | Sep 14 | Sep 19 | Sep 21 | Sep 24 | Sep 26 | Sep 29 | Oct 4 |
| 32°F | Sep 14 | Sep 21 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 9 | Oct 13 | Oct 18 |
| 28°F | Sep 26 | Oct 3 | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 24 | Oct 29 |
| 24°F | Oct 6 | Oct 12 | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 5 | Nov 12 |
| 20°F | Oct 19 | Oct 25 | Oct 30 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 18 | Nov 24 |
| 16°F | Oct 27 | Nov 3 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 26 | Dec 2 |
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 | 131 | 123 | 116 | 112 | 108 | 103 | 99 | 94 | 86 |
| 32°F | 162 | 153 | 148 | 143 | 137 | 132 | 126 | 120 | 111 |
| 28°F | 187 | 180 | 175 | 170 | 165 | 160 | 154 | 149 | 139 |
| 24°F | 220 | 209 | 203 | 198 | 192 | 188 | 182 | 176 | 167 |
| 20°F | 251 | 241 | 233 | 227 | 222 | 216 | 211 | 204 | 195 |
| 16°F | 278 | 270 | 262 | 256 | 250 | 244 | 239 | 232 | 221 |
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
- 6,571
- Cooling degree days, base 65°F
- 670
- Growing degree days, base 40°F
- 4,601
- Growing degree days, base 45°F
- 3,515
- Growing degree days, base 50°F
- 2,585
- Growing degree days, base 55°F
- 1,809
- Growing degree days, base 60°F
- 1,171
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,153 | 0 | 0 |
| February | 942 | 0 | 0 |
| March | 784 | 0 | 11 |
| April | 565 | 1 | 55 |
| May | 318 | 17 | 208 |
| June | 120 | 81 | 416 |
| July | 15 | 268 | 717 |
| August | 20 | 234 | 679 |
| September | 145 | 66 | 383 |
| October | 492 | 4 | 105 |
| November | 849 | 0 | 10 |
| December | 1,167 | 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 16.5 km from Inkom. 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 USC00107208 (Pocatello 2 Ne). Public domain.