Clancy Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Tizer Gardens. 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 18 and the first fall freeze around September 5, a growing season of about 81 days.
- Median at 32°F
- last June 18, first September 5
- Median at 28°F
- last May 29, first September 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 | – | – | – | – | – | – | – | – | – |
| 32°F | Jul 3 | Jun 28 | Jun 24 | Jun 21 | Jun 18 | Jun 14 | Jun 10 | Jun 4 | May 30 |
| 28°F | Jun 19 | Jun 11 | Jun 6 | Jun 1 | May 29 | May 25 | May 21 | May 18 | May 12 |
| 24°F | May 28 | May 21 | May 17 | May 14 | May 12 | May 8 | May 5 | May 2 | Apr 27 |
| 20°F | May 12 | May 7 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 20 | Apr 15 | Apr 8 |
| 16°F | May 3 | Apr 28 | Apr 23 | Apr 17 | Apr 13 | Apr 8 | Apr 5 | Apr 2 | Mar 27 |
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 | Aug 21 | Aug 27 | Aug 30 | Sep 2 | Sep 5 | Sep 8 | Sep 11 | Sep 14 | Sep 18 |
| 28°F | Sep 4 | Sep 10 | Sep 13 | Sep 16 | Sep 18 | Sep 21 | Sep 23 | Sep 26 | Oct 1 |
| 24°F | Sep 17 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 10 | Oct 16 |
| 20°F | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 30 |
| 16°F | Oct 2 | Oct 8 | Oct 14 | Oct 17 | Oct 21 | Oct 25 | Oct 30 | Nov 3 | Nov 9 |
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 | 70 | 63 | 57 | 52 | 47 | 43 | 39 | 34 | 29 |
| 32°F | 102 | 95 | 89 | 85 | 81 | 75 | 71 | 65 | 58 |
| 28°F | 132 | 125 | 121 | 115 | 111 | 107 | 103 | 96 | 87 |
| 24°F | 163 | 156 | 151 | 146 | 142 | 138 | 133 | 127 | 120 |
| 20°F | 192 | 184 | 177 | 172 | 167 | 163 | 158 | 154 | 146 |
| 16°F | 217 | 209 | 203 | 197 | 192 | 186 | 181 | 175 | 166 |
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
- 8,802
- Cooling degree days, base 65°F
- 75
- Growing degree days, base 40°F
- 2,778
- Growing degree days, base 45°F
- 1,905
- Growing degree days, base 50°F
- 1,209
- Growing degree days, base 55°F
- 669
- Growing degree days, base 60°F
- 289
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,307 | 0 | 0 |
| February | 1,158 | 0 | 1 |
| March | 1,029 | 0 | 1 |
| April | 767 | 0 | 7 |
| May | 547 | 0 | 59 |
| June | 313 | 6 | 171 |
| July | 100 | 35 | 402 |
| August | 119 | 32 | 382 |
| September | 358 | 3 | 158 |
| October | 740 | 0 | 26 |
| November | 1,028 | 0 | 1 |
| December | 1,337 | 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 10.6 km from Clancy. 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 USC00248239 (Tizer Gardens). Public domain.