Gruver Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Gruver. 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 April 21 and the first fall freeze around October 23, a growing season of about 182 days.
- Median at 36°F
- last April 30, first October 13
- Median at 32°F
- last April 21, first October 23
- Median at 28°F
- last April 10, first November 1
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 13 | May 8 | May 4 | May 2 | Apr 30 | Apr 28 | Apr 25 | Apr 21 | Apr 17 |
| 32°F | May 4 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 7 |
| 28°F | Apr 27 | Apr 21 | Apr 17 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Apr 1 | Mar 26 |
| 24°F | Apr 17 | Apr 11 | Apr 7 | Apr 3 | Mar 31 | Mar 28 | Mar 24 | Mar 18 | Mar 11 |
| 20°F | Apr 6 | Apr 1 | Mar 27 | Mar 22 | Mar 17 | Mar 13 | Mar 9 | Mar 5 | Feb 28 |
| 16°F | Mar 24 | Mar 16 | Mar 11 | Mar 7 | Mar 4 | Mar 1 | Feb 26 | Feb 21 | Feb 15 |
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 29 | Oct 3 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 21 | Oct 25 |
| 32°F | Oct 8 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 3 |
| 28°F | Oct 19 | Oct 23 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 13 |
| 24°F | Oct 27 | Nov 1 | Nov 3 | Nov 6 | Nov 8 | Nov 11 | Nov 13 | Nov 17 | Nov 22 |
| 20°F | Nov 1 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 27 | Dec 2 |
| 16°F | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 12 |
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 | 181 | 175 | 171 | 167 | 165 | 160 | 156 | 152 | 146 |
| 32°F | 201 | 195 | 190 | 186 | 182 | 179 | 175 | 170 | 163 |
| 28°F | 222 | 215 | 211 | 206 | 203 | 199 | 195 | 189 | 182 |
| 24°F | 243 | 236 | 231 | 226 | 222 | 217 | 213 | 208 | 200 |
| 20°F | 266 | 259 | 253 | 247 | 243 | 238 | 233 | 226 | 218 |
| 16°F | 291 | 282 | 275 | 270 | 265 | 260 | 255 | 248 | 238 |
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
- 4,574
- Cooling degree days, base 65°F
- 1,439
- Growing degree days, base 40°F
- 6,708
- Growing degree days, base 45°F
- 5,352
- Growing degree days, base 50°F
- 4,152
- Growing degree days, base 55°F
- 3,106
- Growing degree days, base 60°F
- 2,205
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 942 | 0 | 3 |
| February | 763 | 0 | 13 |
| March | 585 | 2 | 74 |
| April | 327 | 13 | 200 |
| May | 109 | 101 | 464 |
| June | 9 | 295 | 737 |
| July | 2 | 437 | 900 |
| August | 2 | 383 | 846 |
| September | 45 | 180 | 587 |
| October | 270 | 27 | 263 |
| November | 601 | 1 | 60 |
| December | 921 | 0 | 5 |
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 0.2 km from Gruver. 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 USC00413787 (Gruver). Public domain.