Bayard Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Bridgeport. 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 8 and the first fall freeze around October 3, a growing season of about 147 days.
- Median at 36°F
- last May 19, first September 25
- Median at 32°F
- last May 8, first October 3
- Median at 28°F
- last April 29, first October 13
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 | Jun 3 | May 30 | May 25 | May 22 | May 19 | May 16 | May 13 | May 10 | May 6 |
| 32°F | May 23 | May 17 | May 14 | May 11 | May 8 | May 5 | May 3 | Apr 30 | Apr 26 |
| 28°F | May 11 | May 6 | May 3 | May 1 | Apr 29 | Apr 26 | Apr 22 | Apr 18 | Apr 13 |
| 24°F | May 2 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 10 | Apr 5 | Apr 1 |
| 20°F | Apr 23 | Apr 17 | Apr 13 | Apr 9 | Apr 6 | Apr 2 | Mar 30 | Mar 24 | Mar 16 |
| 16°F | Apr 15 | Apr 9 | Apr 3 | Mar 31 | Mar 25 | Mar 19 | Mar 14 | 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 11 | Sep 16 | Sep 20 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 2 | Oct 7 |
| 32°F | Sep 21 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 15 |
| 28°F | Sep 29 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 25 |
| 24°F | Oct 8 | Oct 13 | Oct 17 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Oct 30 | Nov 4 |
| 20°F | Oct 17 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 13 |
| 16°F | Oct 23 | Oct 28 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 22 |
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 | 146 | 139 | 134 | 130 | 126 | 122 | 119 | 115 | 107 |
| 32°F | 164 | 159 | 154 | 151 | 147 | 144 | 140 | 134 | 128 |
| 28°F | 185 | 179 | 173 | 170 | 166 | 162 | 159 | 154 | 148 |
| 24°F | 208 | 200 | 194 | 189 | 186 | 182 | 177 | 172 | 166 |
| 20°F | 230 | 222 | 215 | 210 | 204 | 200 | 195 | 189 | 182 |
| 16°F | 251 | 243 | 237 | 232 | 226 | 220 | 214 | 208 | 199 |
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
- 6,106
- Cooling degree days, base 65°F
- 895
- Growing degree days, base 40°F
- 5,224
- Growing degree days, base 45°F
- 4,063
- Growing degree days, base 50°F
- 3,062
- Growing degree days, base 55°F
- 2,206
- Growing degree days, base 60°F
- 1,487
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 | 0 |
| February | 934 | 0 | 1 |
| March | 744 | 0 | 20 |
| April | 489 | 2 | 88 |
| May | 235 | 33 | 291 |
| June | 37 | 169 | 583 |
| July | 3 | 337 | 799 |
| August | 10 | 268 | 724 |
| September | 105 | 84 | 435 |
| October | 467 | 2 | 112 |
| November | 816 | 0 | 9 |
| December | 1,134 | 0 | 0 |
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 20.7 km from Bayard. 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 USC00251145 (Bridgeport). Public domain.