Dunkirk Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Fredonia. 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 25 and the first fall freeze around November 1, a growing season of about 185 days.
- Median at 36°F
- last May 6, first October 16
- Median at 32°F
- last April 25, first November 1
- Median at 28°F
- last April 14, first November 12
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 21 | May 17 | May 13 | May 9 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 23 |
| 32°F | May 9 | May 4 | Apr 30 | Apr 28 | Apr 25 | Apr 23 | Apr 20 | Apr 17 | Apr 12 |
| 28°F | Apr 27 | Apr 22 | Apr 19 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 4 | Apr 1 |
| 24°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 30 | Mar 26 | Mar 20 |
| 20°F | Apr 6 | Apr 2 | Mar 31 | Mar 28 | Mar 24 | Mar 21 | Mar 18 | Mar 14 | Mar 9 |
| 16°F | Mar 29 | Mar 24 | Mar 21 | Mar 18 | Mar 16 | Mar 13 | Mar 10 | Mar 6 | Feb 28 |
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 2 | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 23 | Oct 27 | Nov 1 |
| 32°F | Oct 13 | Oct 20 | Oct 25 | Oct 28 | Nov 1 | Nov 3 | Nov 5 | Nov 10 | Nov 16 |
| 28°F | Oct 30 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 30 |
| 24°F | Nov 9 | Nov 15 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 2 | Dec 5 | Dec 11 |
| 20°F | Nov 18 | Nov 24 | Nov 29 | Dec 1 | Dec 5 | Dec 8 | Dec 13 | Dec 17 | Dec 22 |
| 16°F | Nov 29 | Dec 4 | Dec 8 | Dec 13 | Dec 16 | Dec 20 | Dec 24 | Dec 28 | Jan 4 |
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 | 183 | 176 | 171 | 167 | 162 | 158 | 154 | 149 | 142 |
| 32°F | 208 | 199 | 194 | 190 | 185 | 182 | 176 | 171 | 163 |
| 28°F | 232 | 225 | 220 | 215 | 211 | 206 | 202 | 197 | 190 |
| 24°F | 255 | 248 | 244 | 239 | 235 | 231 | 225 | 220 | 213 |
| 20°F | 277 | 270 | 264 | 260 | 255 | 251 | 246 | 242 | 234 |
| 16°F | 295 | 289 | 284 | 280 | 275 | 270 | 264 | 260 | 252 |
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
- 5,906
- Cooling degree days, base 65°F
- 714
- Growing degree days, base 40°F
- 5,204
- Growing degree days, base 45°F
- 4,026
- Growing degree days, base 50°F
- 2,986
- Growing degree days, base 55°F
- 2,083
- Growing degree days, base 60°F
- 1,326
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,155 | 0 | 2 |
| February | 1,019 | 0 | 2 |
| March | 888 | 0 | 19 |
| April | 515 | 6 | 93 |
| May | 223 | 42 | 300 |
| June | 47 | 145 | 548 |
| July | 5 | 229 | 688 |
| August | 8 | 194 | 651 |
| September | 82 | 86 | 456 |
| October | 348 | 12 | 180 |
| November | 645 | 0 | 43 |
| December | 970 | 0 | 6 |
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 3.8 km from Dunkirk. 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 USC00303033 (Fredonia). Public domain.