Frost dates / Virginia / Portsmouth
Frost dates in Portsmouth, VA
The station on this page is NORFOLK S, VA US (USC00446147), 7.1 miles from the city point. Population in the Census 2024 estimate is 96,482.
Zone 8bUSDA average annual extreme minimum 15°F to 20°F, from ZIP 23707 (1.5 miles from the city point used on this page).
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 7 | Earlier date. A last 32°F on or after this day is common. |
| 50% | March 23 | Median. |
| 10% | April 6 | 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% | November 4 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | November 16 | Median. |
| 90% | December 1 | 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% | 262 |
| 50% | 239 |
| 90% | 220 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | March 26 | March 10 | February 19 |
| First, on or before | November 14 | December 1 | December 25 |
| Season at least | 295 days | 269 days | 243 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | April 18 | April 5 | March 22 |
| First, on or before | October 27 | November 6 | November 19 |
| Season at least | 236 days | 217 days | 200 days |
Station NORFOLK S, VA US (USC00446147). Completeness flag R, 16 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 3 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.
Check a crop against this station
Portsmouth, VA
Zone 8bAverage annual extreme minimum 15°F to 20°F
Outside the median season Growing seasonTicks: 10%, 50%, and 90%
Virginia. Nearest qualified station: NORFOLK S, VA US (USC00446147), 7.1 miles. Median last 32°F March 23. Median first 32°F November 16. The 50% growing-season length is 239 days.
32°F probabilities at this station
| 10% | 50% | 90% | |
|---|---|---|---|
| Last 32°F on or after | April 6 | March 23 | March 7 |
| First 32°F on or before | November 4 | November 16 | December 1 |
Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

Planting calendar
Frost dates for Virginia are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.
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