Ware Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Belchertown. 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 May 3 and the first fall freeze around October 14, a growing season of about 164 days.
- Median at 36°F
- last May 13, first October 4
- Median at 32°F
- last May 3, first October 14
- Median at 28°F
- last April 20, first October 27
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 25 | May 22 | May 19 | May 16 | May 13 | May 10 | May 7 | May 4 | Apr 30 |
| 32°F | May 16 | May 11 | May 8 | May 5 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 21 |
| 28°F | May 4 | May 1 | Apr 27 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 |
| 24°F | Apr 20 | Apr 15 | Apr 11 | Apr 8 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 26 |
| 20°F | Apr 7 | Apr 3 | Apr 1 | Mar 30 | Mar 28 | Mar 25 | Mar 21 | Mar 17 | Mar 13 |
| 16°F | Mar 31 | Mar 28 | Mar 24 | Mar 20 | Mar 17 | Mar 15 | Mar 12 | Mar 8 | Mar 3 |
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 23 | Sep 27 | Oct 1 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 16 |
| 32°F | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
| 28°F | Oct 12 | Oct 17 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 9 |
| 24°F | Oct 25 | Oct 31 | Nov 2 | Nov 5 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 23 |
| 20°F | Nov 5 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 7 |
| 16°F | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 1 | Dec 4 | Dec 7 | Dec 11 | Dec 19 |
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 | 160 | 155 | 150 | 147 | 144 | 141 | 137 | 132 | 126 |
| 32°F | 184 | 177 | 172 | 168 | 164 | 160 | 156 | 151 | 145 |
| 28°F | 209 | 202 | 197 | 193 | 189 | 185 | 181 | 176 | 169 |
| 24°F | 236 | 229 | 223 | 218 | 214 | 210 | 206 | 201 | 195 |
| 20°F | 259 | 252 | 247 | 243 | 238 | 234 | 230 | 225 | 218 |
| 16°F | 278 | 271 | 266 | 262 | 257 | 253 | 250 | 245 | 238 |
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
- 6,774
- Cooling degree days, base 65°F
- 488
- Growing degree days, base 40°F
- 4,475
- Growing degree days, base 45°F
- 3,398
- Growing degree days, base 50°F
- 2,467
- Growing degree days, base 55°F
- 1,666
- Growing degree days, base 60°F
- 1,000
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,265 | 0 | 0 |
| February | 1,113 | 0 | 0 |
| March | 970 | 0 | 7 |
| April | 597 | 2 | 47 |
| May | 279 | 17 | 231 |
| June | 67 | 82 | 466 |
| July | 11 | 190 | 645 |
| August | 18 | 144 | 590 |
| September | 136 | 51 | 367 |
| October | 466 | 2 | 98 |
| November | 764 | 0 | 15 |
| December | 1,088 | 0 | 1 |
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 9.2 km from Ware. 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 USC00190562 (Belchertown). Public domain.