Hughes County Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Harrold 12 Ssw. 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 17 and the first fall freeze around September 24, a growing season of about 129 days.
- Median at 36°F
- last May 27, first September 16
- Median at 32°F
- last May 17, first September 24
- Median at 28°F
- last May 8, first October 2
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 10 | Jun 5 | Jun 2 | May 31 | May 27 | May 24 | May 22 | May 18 | May 13 |
| 32°F | May 31 | May 27 | May 23 | May 21 | May 17 | May 15 | May 12 | May 9 | May 4 |
| 28°F | May 22 | May 17 | May 14 | May 11 | May 8 | May 6 | May 3 | Apr 30 | Apr 25 |
| 24°F | May 13 | May 8 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 15 |
| 20°F | May 5 | May 1 | Apr 28 | Apr 24 | Apr 20 | Apr 16 | Apr 13 | Apr 9 | Apr 3 |
| 16°F | Apr 27 | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 24 |
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 6 | Sep 10 | Sep 13 | Sep 16 | Sep 18 | Sep 21 | Sep 24 | Sep 28 |
| 32°F | Sep 10 | Sep 15 | Sep 19 | Sep 22 | Sep 24 | Sep 26 | Sep 29 | Oct 2 | Oct 6 |
| 28°F | Sep 18 | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 6 | Oct 10 | Oct 14 |
| 24°F | Sep 25 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 24 |
| 20°F | Oct 3 | Oct 8 | Oct 13 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 |
| 16°F | Oct 12 | Oct 17 | Oct 21 | Oct 25 | Oct 27 | Oct 30 | Nov 2 | Nov 5 | Nov 10 |
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 | 129 | 123 | 118 | 114 | 110 | 107 | 103 | 98 | 88 |
| 32°F | 146 | 140 | 136 | 132 | 129 | 125 | 121 | 116 | 109 |
| 28°F | 166 | 159 | 154 | 150 | 146 | 142 | 138 | 133 | 126 |
| 24°F | 184 | 177 | 172 | 167 | 164 | 160 | 156 | 149 | 142 |
| 20°F | 202 | 195 | 190 | 185 | 181 | 176 | 172 | 167 | 160 |
| 16°F | 222 | 214 | 209 | 204 | 200 | 196 | 191 | 185 | 175 |
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
- 8,161
- Cooling degree days, base 65°F
- 657
- Growing degree days, base 40°F
- 4,378
- Growing degree days, base 45°F
- 3,395
- Growing degree days, base 50°F
- 2,533
- Growing degree days, base 55°F
- 1,783
- Growing degree days, base 60°F
- 1,156
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,544 | 0 | 0 |
| February | 1,263 | 0 | 0 |
| March | 1,039 | 0 | 8 |
| April | 656 | 1 | 47 |
| May | 330 | 20 | 214 |
| June | 78 | 105 | 478 |
| July | 15 | 250 | 700 |
| August | 29 | 206 | 642 |
| September | 176 | 73 | 363 |
| October | 594 | 3 | 78 |
| November | 1,016 | 0 | 3 |
| December | 1,423 | 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 15.6 km from Hughes County. 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 USC00393608 (Harrold 12 Ssw). Public domain.