Clearview Acres Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Rock Springs Fire Dept. 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 24 and the first fall freeze around September 24, a growing season of about 121 days.
- Median at 36°F
- last June 6, first September 14
- Median at 32°F
- last May 24, first September 24
- Median at 28°F
- last May 9, 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 | Jun 21 | Jun 16 | Jun 12 | Jun 9 | Jun 6 | Jun 3 | Jun 1 | May 29 | May 24 |
| 32°F | Jun 9 | Jun 3 | May 31 | May 28 | May 24 | May 21 | May 17 | May 14 | May 8 |
| 28°F | May 26 | May 20 | May 15 | May 12 | May 9 | May 6 | May 3 | Apr 30 | Apr 25 |
| 24°F | May 11 | May 7 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 20 | Apr 15 | Apr 10 |
| 20°F | Apr 29 | Apr 23 | Apr 18 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 21 |
| 16°F | Apr 15 | Apr 7 | Apr 2 | Mar 30 | Mar 24 | Mar 19 | Mar 15 | Mar 11 | Mar 6 |
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 2 | Sep 5 | Sep 9 | Sep 11 | Sep 14 | Sep 16 | Sep 19 | Sep 22 | Sep 25 |
| 32°F | Sep 9 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 4 |
| 28°F | Sep 19 | Sep 23 | Sep 27 | Sep 30 | Oct 3 | Oct 5 | Oct 8 | Oct 12 | Oct 17 |
| 24°F | Sep 29 | Oct 4 | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 28 |
| 20°F | Oct 9 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 8 |
| 16°F | Oct 21 | Oct 26 | Oct 31 | Nov 2 | Nov 5 | Nov 7 | Nov 10 | Nov 14 | Nov 19 |
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 | 116 | 110 | 105 | 101 | 97 | 94 | 90 | 86 | 79 |
| 32°F | 141 | 134 | 130 | 125 | 121 | 118 | 112 | 107 | 99 |
| 28°F | 166 | 160 | 155 | 150 | 146 | 141 | 136 | 131 | 124 |
| 24°F | 193 | 185 | 178 | 174 | 170 | 165 | 161 | 155 | 147 |
| 20°F | 220 | 212 | 206 | 202 | 197 | 193 | 187 | 181 | 172 |
| 16°F | 246 | 240 | 233 | 227 | 222 | 218 | 212 | 207 | 199 |
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
- 7,553
- Cooling degree days, base 65°F
- 302
- Growing degree days, base 40°F
- 3,814
- Growing degree days, base 45°F
- 2,814
- Growing degree days, base 50°F
- 1,970
- Growing degree days, base 55°F
- 1,276
- Growing degree days, base 60°F
- 715
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,287 | 0 | 0 |
| February | 1,078 | 0 | 0 |
| March | 899 | 0 | 2 |
| April | 655 | 0 | 15 |
| May | 395 | 3 | 135 |
| June | 128 | 35 | 362 |
| July | 11 | 148 | 601 |
| August | 29 | 107 | 544 |
| September | 216 | 9 | 261 |
| October | 578 | 0 | 49 |
| November | 969 | 0 | 1 |
| December | 1,308 | 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 3.1 km from Clearview Acres. 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 USC00487847 (Rock Springs Fire Dept). Public domain.