Fountain Green Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Moroni. 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 26 and the first fall freeze around September 25, a growing season of about 119 days.
- Median at 36°F
- last June 10, first September 16
- Median at 32°F
- last May 26, first September 25
- Median at 28°F
- last May 10, first October 5
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 28 | Jun 22 | Jun 18 | Jun 13 | Jun 10 | Jun 6 | Jun 4 | Jun 1 | May 27 |
| 32°F | Jun 13 | Jun 6 | Jun 3 | May 31 | May 26 | May 23 | May 19 | May 15 | May 10 |
| 28°F | May 30 | May 21 | May 16 | May 13 | May 10 | May 7 | May 3 | Apr 30 | Apr 25 |
| 24°F | May 11 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 16 | Apr 11 |
| 20°F | Apr 29 | Apr 23 | Apr 18 | Apr 14 | Apr 10 | Apr 6 | Apr 2 | Mar 29 | Mar 18 |
| 16°F | Apr 10 | Apr 4 | Mar 30 | Mar 24 | Mar 18 | Mar 13 | Mar 9 | Mar 5 | Feb 28 |
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 1 | Sep 5 | Sep 9 | Sep 13 | Sep 16 | Sep 19 | Sep 21 | Sep 24 | Sep 27 |
| 32°F | Sep 9 | Sep 15 | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 4 | Oct 8 |
| 28°F | Sep 21 | Sep 26 | Sep 29 | Oct 1 | Oct 5 | Oct 7 | Oct 11 | Oct 15 | Oct 20 |
| 24°F | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Nov 1 |
| 20°F | Oct 13 | Oct 19 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 12 |
| 16°F | Oct 25 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 24 |
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 | 115 | 109 | 103 | 98 | 94 | 90 | 85 | 79 | 70 |
| 32°F | 141 | 133 | 128 | 124 | 119 | 115 | 110 | 105 | 98 |
| 28°F | 168 | 160 | 155 | 151 | 147 | 142 | 138 | 132 | 121 |
| 24°F | 193 | 187 | 182 | 177 | 172 | 168 | 162 | 157 | 150 |
| 20°F | 227 | 216 | 211 | 205 | 200 | 195 | 190 | 184 | 177 |
| 16°F | 259 | 251 | 245 | 240 | 234 | 229 | 222 | 215 | 206 |
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
- 6,724
- Cooling degree days, base 65°F
- 381
- Growing degree days, base 40°F
- 4,247
- Growing degree days, base 45°F
- 3,149
- Growing degree days, base 50°F
- 2,223
- Growing degree days, base 55°F
- 1,465
- Growing degree days, base 60°F
- 845
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,224 | 0 | 0 |
| February | 965 | 0 | 0 |
| March | 780 | 0 | 5 |
| April | 576 | 0 | 31 |
| May | 340 | 4 | 169 |
| June | 101 | 47 | 398 |
| July | 9 | 179 | 635 |
| August | 13 | 133 | 584 |
| September | 153 | 18 | 323 |
| October | 496 | 0 | 73 |
| November | 849 | 0 | 4 |
| December | 1,218 | 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 12.2 km from Fountain Green. 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 USC00425837 (Moroni). Public domain.