Warwick Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sussex 3 Wnw. 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 11, a growing season of about 163 days.
- Median at 36°F
- last May 14, first October 2
- Median at 32°F
- last April 30, first October 11
- Median at 28°F
- last April 18, first October 24
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 30 | May 25 | May 20 | May 17 | May 14 | May 10 | May 6 | May 2 | Apr 28 |
| 32°F | May 18 | May 11 | May 7 | May 4 | Apr 30 | Apr 28 | Apr 25 | Apr 21 | Apr 17 |
| 28°F | May 5 | Apr 29 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 8 | Apr 4 |
| 24°F | Apr 17 | Apr 12 | Apr 9 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 28 | Mar 23 |
| 20°F | Apr 5 | Apr 2 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 18 | Mar 13 | Mar 8 |
| 16°F | Mar 29 | Mar 24 | Mar 20 | Mar 17 | Mar 14 | Mar 10 | Mar 7 | Mar 3 | Feb 26 |
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 21 | Sep 25 | Sep 29 | Oct 1 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 15 |
| 32°F | Sep 30 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 | Oct 22 | Oct 27 |
| 28°F | Oct 6 | Oct 11 | Oct 16 | Oct 20 | Oct 24 | Oct 28 | Nov 1 | Nov 4 | Nov 9 |
| 24°F | Oct 20 | Oct 25 | Oct 30 | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 16 | Nov 22 |
| 20°F | Nov 1 | Nov 6 | Nov 11 | Nov 15 | Nov 19 | Nov 23 | Nov 26 | Dec 1 | Dec 6 |
| 16°F | Nov 12 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 21 |
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 | 162 | 155 | 149 | 144 | 141 | 136 | 131 | 127 | 121 |
| 32°F | 184 | 177 | 173 | 168 | 163 | 159 | 153 | 147 | 140 |
| 28°F | 209 | 201 | 196 | 192 | 187 | 184 | 179 | 173 | 166 |
| 24°F | 236 | 229 | 223 | 220 | 215 | 210 | 206 | 201 | 194 |
| 20°F | 263 | 255 | 249 | 244 | 240 | 235 | 230 | 225 | 218 |
| 16°F | 286 | 278 | 272 | 267 | 262 | 257 | 252 | 246 | 239 |
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
- 6,312
- Cooling degree days, base 65°F
- 587
- Growing degree days, base 40°F
- 4,797
- Growing degree days, base 45°F
- 3,668
- Growing degree days, base 50°F
- 2,682
- Growing degree days, base 55°F
- 1,834
- Growing degree days, base 60°F
- 1,134
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,215 | 0 | 0 |
| February | 1,037 | 0 | 1 |
| March | 893 | 0 | 11 |
| April | 522 | 4 | 78 |
| May | 240 | 28 | 267 |
| June | 54 | 106 | 503 |
| July | 7 | 217 | 676 |
| August | 15 | 170 | 620 |
| September | 129 | 57 | 382 |
| October | 429 | 5 | 123 |
| November | 723 | 0 | 21 |
| December | 1,049 | 0 | 3 |
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 25.6 km from Warwick. 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 USC00288644 (Sussex 3 Wnw). Public domain.