Bedford Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Bedford. 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 7 and the first fall freeze around October 31, a growing season of about 204 days.
- Median at 36°F
- last April 20, first October 22
- Median at 32°F
- last April 7, first October 31
- Median at 28°F
- last March 29, first November 9
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 1 | Apr 28 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 |
| 32°F | Apr 24 | Apr 18 | Apr 15 | Apr 11 | Apr 7 | Apr 5 | Apr 3 | Mar 31 | Mar 25 |
| 28°F | Apr 13 | Apr 7 | Apr 3 | Mar 31 | Mar 29 | Mar 25 | Mar 21 | Mar 17 | Mar 11 |
| 24°F | Apr 2 | Mar 29 | Mar 24 | Mar 20 | Mar 16 | Mar 13 | Mar 9 | Mar 4 | Feb 27 |
| 20°F | Mar 23 | Mar 16 | Mar 12 | Mar 8 | Mar 3 | Feb 28 | Feb 24 | Feb 19 | Feb 11 |
| 16°F | Mar 14 | Mar 6 | Mar 1 | Feb 25 | Feb 19 | Feb 14 | Feb 9 | Feb 4 | Jan 29 |
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 8 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 24 | Oct 26 | Oct 29 | Nov 1 |
| 32°F | Oct 16 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 8 | Nov 12 |
| 28°F | Oct 28 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 25 |
| 24°F | Nov 7 | Nov 13 | Nov 17 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 17 |
| 20°F | Nov 22 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 19 | Dec 25 | Jan 1 | Jan 9 |
| 16°F | Dec 7 | Dec 14 | Dec 21 | Dec 27 | Jan 1 | Jan 5 | Jan 10 | Jan 16 | Jan 26 |
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 | 201 | 195 | 190 | 186 | 182 | 179 | 174 | 170 | 163 |
| 32°F | 223 | 216 | 211 | 207 | 204 | 200 | 196 | 191 | 182 |
| 28°F | 250 | 240 | 234 | 229 | 225 | 221 | 216 | 211 | 204 |
| 24°F | 279 | 268 | 262 | 257 | 252 | 246 | 241 | 235 | 226 |
| 20°F | 311 | 302 | 295 | 289 | 284 | 278 | 272 | 264 | 254 |
| 16°F | 334 | 326 | 319 | 313 | 307 | 302 | 297 | 290 | 280 |
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
- 4,062
- Cooling degree days, base 65°F
- 1,162
- Growing degree days, base 40°F
- 6,651
- Growing degree days, base 45°F
- 5,218
- Growing degree days, base 50°F
- 3,955
- Growing degree days, base 55°F
- 2,857
- Growing degree days, base 60°F
- 1,926
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 857 | 0 | 11 |
| February | 722 | 0 | 11 |
| March | 560 | 4 | 73 |
| April | 255 | 27 | 249 |
| May | 98 | 75 | 443 |
| June | 13 | 225 | 663 |
| July | 1 | 359 | 823 |
| August | 1 | 309 | 773 |
| September | 35 | 147 | 563 |
| October | 248 | 14 | 250 |
| November | 510 | 1 | 81 |
| December | 763 | 0 | 16 |
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 1.4 km from Bedford. 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 USC00440551 (Bedford). Public domain.