Dublin Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sellersville. 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 26 and the first fall freeze around October 17, a growing season of about 175 days.
- Median at 36°F
- last May 6, first October 7
- Median at 32°F
- last April 26, first October 17
- Median at 28°F
- last April 13, first October 28
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 23 | May 18 | May 13 | May 10 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 23 |
| 32°F | May 12 | May 6 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 20 | Apr 17 | Apr 12 |
| 28°F | Apr 30 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 10 | Apr 7 | Apr 3 | Mar 30 |
| 24°F | Apr 16 | Apr 10 | Apr 6 | Apr 4 | Apr 1 | Mar 30 | Mar 27 | Mar 22 | Mar 17 |
| 20°F | Apr 5 | Mar 31 | Mar 29 | Mar 25 | Mar 21 | Mar 18 | Mar 15 | Mar 10 | Mar 5 |
| 16°F | Mar 26 | Mar 21 | Mar 17 | Mar 14 | Mar 10 | Mar 6 | Mar 2 | Feb 26 | Feb 21 |
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 28 | Oct 1 | Oct 3 | Oct 6 | Oct 7 | Oct 10 | Oct 13 | Oct 17 | Oct 22 |
| 32°F | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Nov 1 |
| 28°F | Oct 13 | Oct 18 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 10 |
| 24°F | Oct 23 | Oct 29 | Nov 2 | Nov 5 | Nov 9 | Nov 11 | Nov 14 | Nov 19 | Nov 25 |
| 20°F | Nov 2 | Nov 9 | Nov 13 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 3 | Dec 11 |
| 16°F | Nov 15 | Nov 22 | Nov 28 | Dec 1 | Dec 6 | Dec 11 | Dec 16 | Dec 21 | Dec 27 |
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 | 173 | 166 | 161 | 157 | 154 | 149 | 145 | 140 | 134 |
| 32°F | 195 | 188 | 183 | 179 | 175 | 171 | 167 | 163 | 156 |
| 28°F | 220 | 213 | 207 | 203 | 198 | 194 | 190 | 184 | 177 |
| 24°F | 244 | 236 | 231 | 226 | 223 | 219 | 214 | 209 | 203 |
| 20°F | 271 | 262 | 256 | 251 | 246 | 241 | 236 | 230 | 222 |
| 16°F | 296 | 289 | 282 | 276 | 271 | 265 | 261 | 255 | 245 |
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
- 5,724
- Cooling degree days, base 65°F
- 786
- Growing degree days, base 40°F
- 5,290
- Growing degree days, base 45°F
- 4,099
- Growing degree days, base 50°F
- 3,059
- Growing degree days, base 55°F
- 2,157
- Growing degree days, base 60°F
- 1,396
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,133 | 0 | 1 |
| February | 959 | 0 | 1 |
| March | 823 | 0 | 17 |
| April | 461 | 6 | 106 |
| May | 196 | 36 | 315 |
| June | 39 | 147 | 558 |
| July | 2 | 280 | 742 |
| August | 7 | 222 | 680 |
| September | 83 | 86 | 454 |
| October | 386 | 8 | 152 |
| November | 671 | 0 | 27 |
| December | 964 | 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 9.6 km from Dublin. 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 USC00367938 (Sellersville). Public domain.