Lander Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Lander Hunt Fld AP. 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 18 and the first fall freeze around September 27, a growing season of about 131 days.
- Median at 36°F
- last June 1, first September 19
- Median at 32°F
- last May 18, first September 27
- Median at 28°F
- last May 4, 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 | Jun 16 | Jun 11 | Jun 7 | Jun 4 | Jun 1 | May 30 | May 26 | May 23 | May 18 |
| 32°F | Jun 3 | May 29 | May 25 | May 21 | May 18 | May 16 | May 12 | May 9 | May 4 |
| 28°F | May 20 | May 14 | May 10 | May 7 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 22 |
| 24°F | May 8 | May 3 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 6 |
| 20°F | Apr 29 | Apr 22 | Apr 17 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 23 |
| 16°F | Apr 17 | Apr 10 | Apr 5 | Apr 2 | Mar 30 | Mar 25 | Mar 19 | Mar 14 | Mar 9 |
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 7 | Sep 10 | Sep 13 | Sep 16 | Sep 19 | Sep 21 | Sep 23 | Sep 26 | Sep 29 |
| 32°F | Sep 13 | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 10 |
| 28°F | Sep 23 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 8 | Oct 12 | Oct 15 | Oct 20 |
| 24°F | Oct 1 | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 29 |
| 20°F | Oct 6 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 2 | Nov 8 |
| 16°F | Oct 15 | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 11 | Nov 16 |
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 | 126 | 121 | 116 | 112 | 107 | 104 | 100 | 96 | 90 |
| 32°F | 151 | 145 | 140 | 136 | 131 | 128 | 123 | 118 | 112 |
| 28°F | 173 | 166 | 162 | 157 | 153 | 149 | 145 | 139 | 134 |
| 24°F | 196 | 189 | 183 | 179 | 174 | 169 | 165 | 159 | 151 |
| 20°F | 216 | 210 | 204 | 200 | 196 | 192 | 187 | 181 | 172 |
| 16°F | 240 | 231 | 225 | 220 | 215 | 210 | 205 | 200 | 190 |
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
- 7,711
- Cooling degree days, base 65°F
- 485
- Growing degree days, base 40°F
- 4,091
- Growing degree days, base 45°F
- 3,089
- Growing degree days, base 50°F
- 2,237
- Growing degree days, base 55°F
- 1,526
- Growing degree days, base 60°F
- 940
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,355 | 0 | 0 |
| February | 1,121 | 0 | 0 |
| March | 899 | 0 | 5 |
| April | 653 | 0 | 30 |
| May | 385 | 5 | 157 |
| June | 124 | 59 | 391 |
| July | 14 | 214 | 665 |
| August | 25 | 174 | 614 |
| September | 195 | 33 | 311 |
| October | 607 | 1 | 61 |
| November | 987 | 0 | 3 |
| December | 1,347 | 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 2 km from Lander. 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 USW00024021 (Lander Hunt Fld AP). Public domain.