Edgewater Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Annapolis Naf. 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 March 23 and the first fall freeze around November 20, a growing season of about 241 days.
- Median at 36°F
- last April 5, first November 6
- Median at 32°F
- last March 23, first November 20
- Median at 28°F
- last March 12, first December 3
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 | Apr 20 | Apr 16 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Mar 31 | Mar 28 | Mar 22 |
| 32°F | Apr 6 | Apr 2 | Mar 31 | Mar 27 | Mar 23 | Mar 20 | Mar 18 | Mar 13 | Mar 8 |
| 28°F | Mar 28 | Mar 22 | Mar 18 | Mar 15 | Mar 12 | Mar 8 | Mar 5 | Mar 1 | Feb 24 |
| 24°F | Mar 19 | Mar 13 | Mar 8 | Mar 4 | Mar 1 | Feb 26 | Feb 22 | Feb 16 | Feb 9 |
| 20°F | Mar 7 | Mar 1 | Feb 25 | Feb 19 | Feb 14 | Feb 9 | Feb 4 | Jan 31 | Jan 19 |
| 16°F | Feb 25 | Feb 16 | Feb 8 | Feb 4 | Jan 31 | Jan 27 | Jan 19 | Jan 14 | Jan 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 | Oct 25 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 21 |
| 32°F | Nov 4 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 23 | Nov 27 | Dec 1 | Dec 5 |
| 28°F | Nov 16 | Nov 22 | Nov 27 | Dec 1 | Dec 3 | Dec 6 | Dec 10 | Dec 15 | Dec 22 |
| 24°F | Nov 30 | Dec 4 | Dec 8 | Dec 13 | Dec 18 | Dec 21 | Dec 25 | Dec 31 | Jan 9 |
| 20°F | Dec 10 | Dec 18 | Dec 22 | Dec 26 | Dec 31 | Jan 4 | Jan 10 | Jan 16 | Jan 26 |
| 16°F | Dec 21 | Dec 26 | Jan 1 | Jan 5 | Jan 10 | Jan 15 | Jan 18 | Jan 26 | Feb 4 |
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 | 234 | 227 | 223 | 219 | 215 | 210 | 205 | 200 | 193 |
| 32°F | 265 | 255 | 250 | 245 | 241 | 236 | 232 | 226 | 219 |
| 28°F | 291 | 281 | 276 | 271 | 266 | 261 | 256 | 250 | 242 |
| 24°F | 316 | 307 | 301 | 296 | 291 | 286 | 280 | 275 | 267 |
| 20°F | 347 | 333 | 327 | 320 | 314 | 308 | 304 | 298 | 288 |
| 16°F | 365 | 365 | 355 | 345 | 337 | 333 | 327 | 319 | 307 |
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
- 97% of years
- 16°F or colder
- 79% 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
- 1,436
- Growing degree days, base 40°F
- 6,926
- Growing degree days, base 45°F
- 5,500
- Growing degree days, base 50°F
- 4,246
- Growing degree days, base 55°F
- 3,150
- Growing degree days, base 60°F
- 2,221
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 885 | 0 | 5 |
| February | 746 | 0 | 13 |
| March | 599 | 1 | 54 |
| April | 301 | 14 | 196 |
| May | 85 | 90 | 470 |
| June | 4 | 292 | 738 |
| July | 0 | 432 | 897 |
| August | 0 | 375 | 840 |
| September | 15 | 198 | 633 |
| October | 198 | 33 | 307 |
| November | 474 | 1 | 77 |
| December | 755 | 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 9.3 km from Edgewater. 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 USW00013752 (Annapolis Naf). Public domain.