Emily Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Pine Rvr 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 May 6 and the first fall freeze around October 7, a growing season of about 152 days.
- Median at 36°F
- last May 16, first September 27
- Median at 32°F
- last May 6, first October 7
- Median at 28°F
- last April 29, first October 18
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 29 | May 25 | May 22 | May 19 | May 16 | May 14 | May 11 | May 8 | May 4 |
| 32°F | May 19 | May 15 | May 11 | May 9 | May 6 | May 4 | May 3 | Apr 30 | Apr 26 |
| 28°F | May 9 | May 5 | May 3 | Apr 30 | Apr 29 | Apr 26 | Apr 23 | Apr 19 | Apr 14 |
| 24°F | Apr 30 | Apr 28 | Apr 24 | Apr 21 | Apr 19 | Apr 16 | Apr 12 | Apr 9 | Apr 5 |
| 20°F | Apr 23 | Apr 19 | Apr 15 | Apr 12 | Apr 10 | Apr 7 | Apr 5 | Apr 2 | Mar 30 |
| 16°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 30 | Mar 25 | Mar 19 |
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 15 | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 29 | Oct 1 | Oct 4 | Oct 9 |
| 32°F | Sep 24 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 16 | Oct 20 |
| 28°F | Oct 4 | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Nov 1 |
| 24°F | Oct 15 | Oct 21 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 20°F | Oct 26 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 11 | Nov 15 | Nov 19 |
| 16°F | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 16 | Nov 19 | Nov 22 | 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 | 149 | 143 | 139 | 136 | 132 | 129 | 125 | 121 | 114 |
| 32°F | 169 | 163 | 159 | 155 | 152 | 148 | 144 | 140 | 135 |
| 28°F | 191 | 184 | 180 | 176 | 172 | 169 | 165 | 161 | 154 |
| 24°F | 211 | 204 | 199 | 196 | 192 | 189 | 185 | 181 | 175 |
| 20°F | 228 | 222 | 217 | 213 | 208 | 205 | 202 | 197 | 192 |
| 16°F | 244 | 237 | 232 | 228 | 224 | 221 | 216 | 211 | 205 |
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
- 8,954
- Cooling degree days, base 65°F
- 406
- Growing degree days, base 40°F
- 3,921
- Growing degree days, base 45°F
- 2,982
- Growing degree days, base 50°F
- 2,154
- Growing degree days, base 55°F
- 1,443
- Growing degree days, base 60°F
- 855
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,734 | 0 | 0 |
| February | 1,431 | 0 | 0 |
| March | 1,173 | 0 | 2 |
| April | 725 | 0 | 29 |
| May | 340 | 16 | 194 |
| June | 85 | 78 | 444 |
| July | 22 | 168 | 611 |
| August | 37 | 116 | 544 |
| September | 219 | 28 | 277 |
| October | 621 | 1 | 52 |
| November | 1,053 | 0 | 2 |
| December | 1,514 | 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 13.4 km from Emily. 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 USC00216547 (Pine Rvr Dam). Public domain.