La Pine Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Wickiup 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 June 7 and the first fall freeze around September 18, a growing season of about 100 days.
- Median at 32°F
- last June 7, first September 18
- Median at 28°F
- last May 16, first October 3
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 | Jul 2 | Jun 21 | Jun 16 | Jun 12 | Jun 7 | Jun 2 | May 29 | May 23 | May 16 |
| 28°F | Jun 13 | Jun 3 | May 28 | May 20 | May 16 | May 11 | May 7 | May 2 | Apr 28 |
| 24°F | May 23 | May 12 | May 6 | May 2 | Apr 29 | Apr 25 | Apr 18 | Apr 10 | Apr 2 |
| 20°F | May 6 | Apr 29 | Apr 19 | Apr 10 | Apr 3 | Mar 29 | Mar 24 | Mar 16 | Mar 8 |
| 16°F | Apr 18 | Mar 30 | Mar 22 | Mar 15 | Mar 9 | Mar 5 | Mar 1 | Feb 24 | Feb 17 |
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 3 | Sep 8 | Sep 12 | Sep 15 | Sep 18 | Sep 21 | Sep 25 | Sep 28 | Oct 3 |
| 28°F | Sep 17 | Sep 23 | Sep 27 | Oct 1 | Oct 3 | Oct 5 | Oct 9 | Oct 13 | Oct 18 |
| 24°F | Oct 2 | Oct 7 | Oct 12 | Oct 16 | Oct 19 | Oct 23 | Oct 28 | Nov 1 | Nov 8 |
| 20°F | Oct 14 | Oct 20 | Oct 25 | Oct 30 | Nov 2 | Nov 6 | Nov 12 | Nov 18 | Nov 26 |
| 16°F | Oct 24 | Nov 1 | Nov 7 | Nov 13 | Nov 18 | Nov 23 | Nov 29 | Dec 3 | Dec 11 |
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 | 90 | 83 | 76 | 70 | 65 | 60 | 54 | 48 | 39 |
| 32°F | 128 | 119 | 112 | 106 | 100 | 94 | 88 | 81 | 69 |
| 28°F | 167 | 158 | 151 | 146 | 141 | 135 | 127 | 119 | 107 |
| 24°F | 205 | 194 | 186 | 180 | 174 | 168 | 161 | 154 | 145 |
| 20°F | 249 | 238 | 229 | 221 | 214 | 206 | 197 | 188 | 176 |
| 16°F | 279 | 269 | 262 | 254 | 248 | 241 | 233 | 224 | 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
- 7,252
- Cooling degree days, base 65°F
- 164
- Growing degree days, base 40°F
- 3,271
- Growing degree days, base 45°F
- 2,296
- Growing degree days, base 50°F
- 1,514
- Growing degree days, base 55°F
- 901
- Growing degree days, base 60°F
- 447
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,073 | 0 | 0 |
| February | 910 | 0 | 0 |
| March | 871 | 0 | 1 |
| April | 696 | 0 | 15 |
| May | 471 | 1 | 99 |
| June | 270 | 15 | 222 |
| July | 81 | 77 | 463 |
| August | 90 | 59 | 436 |
| September | 256 | 11 | 229 |
| October | 572 | 0 | 48 |
| November | 863 | 0 | 2 |
| December | 1,100 | 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 14.8 km from La Pine. 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 USC00359316 (Wickiup Dam). Public domain.