Edmond Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Guthrie 5S. 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 10 and the first fall freeze around October 28, a growing season of about 199 days.
- Median at 36°F
- last April 22, first October 19
- Median at 32°F
- last April 10, first October 28
- Median at 28°F
- last March 30, first November 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 | May 7 | May 2 | Apr 30 | Apr 25 | Apr 22 | Apr 19 | Apr 15 | Apr 11 | Apr 6 |
| 32°F | Apr 30 | Apr 22 | Apr 18 | Apr 13 | Apr 10 | Apr 6 | Apr 4 | Mar 30 | Mar 24 |
| 28°F | Apr 17 | Apr 10 | Apr 6 | Apr 3 | Mar 30 | Mar 26 | Mar 22 | Mar 17 | Mar 11 |
| 24°F | Apr 5 | Mar 31 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 9 | Mar 4 | Feb 27 |
| 20°F | Mar 23 | Mar 16 | Mar 12 | Mar 9 | Mar 5 | Mar 2 | Feb 27 | Feb 23 | Feb 16 |
| 16°F | Mar 13 | Mar 9 | Mar 4 | Feb 28 | Feb 24 | Feb 21 | Feb 15 | Feb 8 | Jan 30 |
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 | Oct 4 | Oct 9 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Nov 1 |
| 32°F | Oct 14 | Oct 19 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 10 |
| 28°F | Oct 23 | Oct 28 | Oct 31 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 22 |
| 24°F | Oct 31 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 22 | Nov 27 | Dec 2 |
| 20°F | Nov 6 | Nov 13 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 13 |
| 16°F | Nov 14 | Nov 24 | Nov 29 | Dec 3 | Dec 7 | Dec 12 | Dec 19 | Dec 24 | Jan 2 |
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 | 199 | 192 | 187 | 183 | 179 | 175 | 170 | 166 | 159 |
| 32°F | 222 | 214 | 208 | 204 | 199 | 195 | 191 | 186 | 178 |
| 28°F | 243 | 234 | 229 | 224 | 220 | 216 | 212 | 207 | 197 |
| 24°F | 266 | 258 | 252 | 246 | 241 | 236 | 230 | 225 | 216 |
| 20°F | 292 | 282 | 275 | 269 | 264 | 259 | 253 | 247 | 235 |
| 16°F | 318 | 307 | 301 | 294 | 289 | 283 | 276 | 269 | 259 |
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
- 3,811
- Cooling degree days, base 65°F
- 1,917
- Growing degree days, base 40°F
- 7,746
- Growing degree days, base 45°F
- 6,289
- Growing degree days, base 50°F
- 4,979
- Growing degree days, base 55°F
- 3,812
- Growing degree days, base 60°F
- 2,794
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 870 | 0 | 14 |
| February | 670 | 1 | 37 |
| March | 483 | 12 | 138 |
| April | 224 | 47 | 304 |
| May | 63 | 148 | 552 |
| June | 4 | 358 | 804 |
| July | 0 | 535 | 1,000 |
| August | 0 | 492 | 956 |
| September | 24 | 254 | 680 |
| October | 190 | 64 | 361 |
| November | 488 | 6 | 109 |
| December | 796 | 1 | 25 |
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 19.6 km from Edmond. 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 USC00343821 (Guthrie 5S). Public domain.