Portsmouth, Virginia: planting zone & frost dates
Portsmouth is in USDA plant hardiness zone 8b, where the average coldest winter night reaches 15 to 20°F (-9.4 to -6.7°C). The typical last spring frost is around Mar 30 and the first fall frost around Nov 11.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 6 | Nov 4 |
| Typical planning date (30% risk) | Mar 30 | Nov 11 |
| Median (50%) | Mar 23 | Nov 16 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station NORFOLK S, VA (USC00446147), 7.1 mi (11.5 km) from the city center and 3 ft lower than the city center (-1 m). Record used for the 1991–2020 normals: 16 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Portsmouth
Portsmouth spans more than one half-zone. Share of the city's land area by zone (via its 7 ZIP codes): 8b (70%), 8a (30%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Portsmouth
Dates are counted from the 30%-risk frost dates above (last frost Mar 30, first frost Nov 11). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 2 – Feb 16 | Apr 6 – Apr 20 | — | — |
| Pepper | Jan 19 – Feb 2 | Apr 13 – Apr 27 | — | — |
| Lettuce | Feb 16 – Mar 2 | Mar 16 – Apr 6 | Mar 2 – Apr 13 | Sep 2 – Sep 30 |
| Green Beans | — | — | Apr 6 – May 11 | Aug 19 – Sep 2 |
| Sweet Corn | — | — | Apr 6 – May 4 | — |
| Zucchini & Summer Squash | Mar 2 – Mar 9 | Apr 6 – Apr 20 | Apr 6 – Apr 27 | Aug 19 – Sep 2 |
| Cucumber | Mar 2 – Mar 9 | Apr 13 – Apr 20 | Apr 6 – Apr 27 | Aug 19 – Sep 2 |
| Carrot | — | — | Mar 9 – Apr 13 | Aug 19 – Sep 2 |
| Onion | Jan 5 – Jan 19 | Mar 2 – Mar 16 | — | — |
| Potato | — | Mar 2 – Mar 23 | — | — |
| Basil | Feb 16 – Mar 2 | Apr 13 – Apr 27 | Apr 13 – May 4 | — |
| Spinach | — | — | Feb 16 – Mar 16 | Sep 16 – Oct 14 |
| Kale | Feb 2 – Feb 16 | Mar 2 – Mar 23 | Mar 2 – Mar 23 | Sep 2 – Sep 30 |
| Broccoli | Feb 2 – Feb 16 | Mar 16 – Apr 6 | — | Aug 19 – Sep 2 |
| Peas | — | — | Feb 16 – Mar 9 | Sep 2 – Sep 16 |
| Eggplant | Jan 19 – Feb 2 | Apr 13 – Apr 27 | — | — |
| Cabbage | Feb 2 – Feb 16 | Mar 2 – Mar 16 | — | Aug 19 – Sep 2 |
| Radish | — | — | Feb 23 – Apr 13 | Sep 30 – Oct 28 |
| Strawberry | — | Mar 2 – Mar 23 | — | — |
| Beets | — | — | Mar 9 – Apr 20 | Sep 2 – Sep 16 |
Nearby cities in Virginia
- Norfolk — zone 8b, last frost Mar 23, first frost Nov 18
- Chesapeake — zone 8a, last frost Mar 29, first frost Nov 12
- Hampton — zone 8b, last frost Mar 30, first frost Nov 10
- Newport News — zone 8a, last frost Apr 7, first frost Nov 4
- Suffolk — zone 8a, last frost Apr 1, first frost Nov 9
- Virginia Beach — zone 8b, last frost Apr 3, first frost Nov 7
More: all Virginia cities · other zone 8b cities: Dallas, TX, Fort Worth, TX, El Paso, TX, Virginia Beach, VA, Arlington, TX, Plano, TX, Irving, TX, Garland, TX
Portsmouth gardening questions
When is the last frost in Portsmouth, VA?
Plan around Mar 30. At NOAA's Norfolk S, VA station, 7.1 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Mar 23, and after Apr 6 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 10. The 90% and 10% dates are 30 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Portsmouth, VA?
Start seeds indoors Feb 2 – Feb 16 and set transplants outside Apr 6 – Apr 20, once nights stay above 50°F and the soil is near 60°F. That leaves 226 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Portsmouth?
About 239 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 220 days, and in 1 year in 10 it runs 262 days or more. In fall there is a 10% chance of frost by Nov 4 and a 30% chance by Nov 11. That ranks 4th longest of 11 Virginia cities on this site.
When should I plant a fall garden in Portsmouth?
Count back from the first fall frost (Nov 11): transplant broccoli Aug 19 – Sep 2; sow kale Sep 2 – Sep 30; sow lettuce Sep 2 – Sep 30; sow radishes Sep 30 – Oct 28. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 1. How the math works: succession and fall planting.
Did Portsmouth's hardiness zone change on the 2023 map?
Yes. Most of Portsmouth was zone 8a on the 2012 map and is zone 8b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
Is all of Portsmouth in zone 8b?
No. Zone 8b covers about 70% of the city's land; the rest is in 8a (30%), measured across the city's 7 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.