ZIP 21705 Zone 7b
Maryland · USDA zone 7b, average annual extreme minimum 5°F to 10°F.
Nearest qualified station: FREDERICK POLICE BRKS, MD US (USC00183348), 1.6 miles from the Census ZCTA internal point for this ZIP.
Outside the median season Growing seasonTicks: 10%, 50%, and 90%
Last 32°F in spring
NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.
| Probability | Date | How to read it |
|---|---|---|
| 90% | March 17 | Earlier date. A last 32°F on or after this day is common. |
| 50% | April 2 | Median. |
| 10% | April 15 | Later date. A last 32°F on or after this day is uncommon. |
First 32°F in fall
NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.
| Probability | Date | How to read it |
|---|---|---|
| 10% | October 23 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | November 6 | Median. |
| 90% | November 24 | Later date. A first 32°F on or before this day is common. |
32°F growing-season length
Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.
| Probability the season is at least this long | Days |
|---|---|
| 10% | 239 |
| 50% | 218 |
| 90% | 196 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | April 4 | March 21 | March 3 |
| First, on or before | November 6 | November 21 | December 11 |
| Season at least | 271 days | 245 days | 223 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | May 2 | April 15 | March 31 |
| First, on or before | October 9 | October 24 | November 6 |
| Season at least | 213 days | 193 days | 170 days |
Station FREDERICK POLICE BRKS, MD US (USC00183348). Completeness flag R, 12 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 115.8 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.