Park View Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Davenport WFO. 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 21 and the first fall freeze around October 17, a growing season of about 176 days.
- Median at 36°F
- last May 1, first October 7
- Median at 32°F
- last April 21, first October 17
- Median at 28°F
- last April 11, first October 26
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 15 | May 10 | May 7 | May 4 | May 1 | Apr 29 | Apr 25 | Apr 21 | Apr 16 |
| 32°F | May 7 | May 2 | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 11 | Apr 7 |
| 28°F | Apr 27 | Apr 22 | Apr 18 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 2 | Mar 30 |
| 24°F | Apr 16 | Apr 10 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 26 | Mar 21 | Mar 15 |
| 20°F | Apr 5 | Apr 1 | Mar 28 | Mar 24 | Mar 20 | Mar 17 | Mar 13 | Mar 10 | Mar 4 |
| 16°F | Mar 28 | Mar 21 | Mar 17 | Mar 14 | Mar 11 | Mar 9 | Mar 5 | Mar 2 | Feb 25 |
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 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 20 |
| 32°F | Oct 3 | Oct 8 | Oct 12 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 24 | Oct 29 |
| 28°F | Oct 13 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 3 | Nov 8 |
| 24°F | Oct 23 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 15 | Nov 20 |
| 20°F | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 26 | Nov 30 |
| 16°F | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 25 | Nov 27 | Dec 1 | Dec 4 | Dec 11 |
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 | 177 | 170 | 166 | 162 | 158 | 155 | 150 | 145 | 139 |
| 32°F | 196 | 189 | 184 | 180 | 176 | 173 | 169 | 164 | 158 |
| 28°F | 216 | 209 | 205 | 201 | 197 | 194 | 189 | 184 | 177 |
| 24°F | 241 | 234 | 227 | 223 | 219 | 214 | 209 | 204 | 197 |
| 20°F | 261 | 254 | 248 | 244 | 240 | 235 | 231 | 225 | 218 |
| 16°F | 279 | 271 | 266 | 262 | 257 | 253 | 248 | 243 | 234 |
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
- 6,397
- Cooling degree days, base 65°F
- 890
- Growing degree days, base 40°F
- 5,396
- Growing degree days, base 45°F
- 4,253
- Growing degree days, base 50°F
- 3,233
- Growing degree days, base 55°F
- 2,333
- Growing degree days, base 60°F
- 1,549
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,350 | 0 | 0 |
| February | 1,095 | 0 | 3 |
| March | 844 | 3 | 35 |
| April | 455 | 6 | 120 |
| May | 168 | 61 | 370 |
| June | 14 | 195 | 631 |
| July | 4 | 282 | 744 |
| August | 9 | 224 | 680 |
| September | 103 | 103 | 455 |
| October | 398 | 15 | 167 |
| November | 778 | 1 | 27 |
| December | 1,181 | 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 9.6 km from Park View. 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 USC00132070 (Davenport WFO). Public domain.