Granger Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sunnyside #2. 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 30 and the first fall freeze around October 8, a growing season of about 160 days.
- Median at 36°F
- last May 15, first September 26
- Median at 32°F
- last April 30, first October 8
- Median at 28°F
- last April 15, first October 22
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 1 | May 25 | May 21 | May 18 | May 15 | May 12 | May 9 | May 7 | May 2 |
| 32°F | May 13 | May 9 | May 5 | May 3 | Apr 30 | Apr 28 | Apr 26 | Apr 23 | Apr 19 |
| 28°F | May 1 | Apr 27 | Apr 23 | Apr 19 | Apr 15 | Apr 12 | Apr 8 | Apr 4 | Mar 30 |
| 24°F | Apr 15 | Apr 7 | Apr 2 | Mar 30 | Mar 26 | Mar 21 | Mar 17 | Mar 11 | Mar 5 |
| 20°F | Mar 27 | Mar 18 | Mar 12 | Mar 7 | Mar 3 | Feb 28 | Feb 24 | Feb 19 | Feb 8 |
| 16°F | Mar 6 | Feb 28 | Feb 25 | Feb 21 | Feb 16 | Feb 9 | Feb 1 | Jan 18 | Jan 5 |
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 11 | Sep 16 | Sep 20 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 5 | Oct 9 |
| 32°F | Sep 26 | Sep 30 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 | Oct 22 |
| 28°F | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Nov 1 | Nov 6 |
| 24°F | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 6 | Nov 10 | Nov 14 | Nov 21 |
| 20°F | Oct 27 | Nov 1 | Nov 7 | Nov 11 | Nov 16 | Nov 20 | Nov 25 | Dec 1 | Dec 8 |
| 16°F | Nov 5 | Nov 14 | Nov 21 | Nov 25 | Nov 30 | Dec 5 | Dec 12 | Dec 21 | Jan 3 |
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 | 153 | 146 | 142 | 137 | 133 | 129 | 124 | 118 | 110 |
| 32°F | 182 | 173 | 168 | 164 | 160 | 156 | 152 | 147 | 141 |
| 28°F | 211 | 204 | 199 | 194 | 190 | 185 | 181 | 174 | 166 |
| 24°F | 251 | 241 | 235 | 228 | 222 | 218 | 212 | 207 | 199 |
| 20°F | 291 | 278 | 270 | 264 | 257 | 251 | 244 | 237 | 228 |
| 16°F | 334 | 320 | 311 | 301 | 294 | 285 | 277 | 268 | 257 |
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
- 98% 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
- 5,831
- Cooling degree days, base 65°F
- 463
- Growing degree days, base 40°F
- 4,689
- Growing degree days, base 45°F
- 3,459
- Growing degree days, base 50°F
- 2,437
- Growing degree days, base 55°F
- 1,605
- Growing degree days, base 60°F
- 945
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,060 | 0 | 0 |
| February | 819 | 0 | 2 |
| March | 682 | 0 | 8 |
| April | 460 | 0 | 61 |
| May | 234 | 5 | 245 |
| June | 102 | 69 | 418 |
| July | 11 | 196 | 650 |
| August | 13 | 155 | 607 |
| September | 136 | 37 | 353 |
| October | 461 | 0 | 85 |
| November | 795 | 0 | 6 |
| December | 1,060 | 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 12.1 km from Granger. 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 USC00458211 (Sunnyside #2). Public domain.