Norwalk, Connecticut: planting zone & frost dates
Norwalk is in USDA plant hardiness zone 7a, where the average coldest winter night reaches 0 to 5°F (-17.8 to -15.0°C). The typical last spring frost is around Apr 23 and the first fall frost around Oct 16.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 2 | Oct 8 |
| Typical planning date (30% risk) | Apr 23 | Oct 16 |
| Median (50%) | Apr 17 | Oct 23 |
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 STAMFORD 5 N, CT (USC00067970), 7.0 mi (11.3 km) from the city center and 174 ft higher than the city center (+53 m). Record used for the 1991–2020 normals: 22 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Norwalk
Norwalk spans more than one half-zone. Share of the city's land area by zone (via its 5 ZIP codes): 7a (90%), 7b (10%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Norwalk
Dates are counted from the 30%-risk frost dates above (last frost Apr 23, first frost Oct 16). 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 26 – Mar 12 | Apr 30 – May 14 | — | — |
| Pepper | Feb 12 – Feb 26 | May 7 – May 21 | — | — |
| Lettuce | Mar 12 – Mar 26 | Apr 9 – Apr 30 | Mar 26 – May 7 | Aug 7 – Sep 4 |
| Green Beans | — | — | Apr 30 – Jun 4 | Jul 24 – Aug 7 |
| Sweet Corn | — | — | Apr 30 – May 28 | — |
| Zucchini & Summer Squash | Mar 26 – Apr 2 | Apr 30 – May 14 | Apr 30 – May 21 | Jul 24 – Aug 7 |
| Cucumber | Mar 26 – Apr 2 | May 7 – May 14 | Apr 30 – May 21 | Jul 24 – Aug 7 |
| Carrot | — | — | Apr 2 – May 7 | Jul 24 – Aug 7 |
| Onion | Jan 29 – Feb 12 | Mar 26 – Apr 9 | — | — |
| Potato | — | Mar 26 – Apr 16 | — | — |
| Basil | Mar 12 – Mar 26 | May 7 – May 21 | May 7 – May 28 | — |
| Spinach | — | — | Mar 12 – Apr 9 | Aug 21 – Sep 18 |
| Kale | Feb 26 – Mar 12 | Mar 26 – Apr 16 | Mar 26 – Apr 16 | Aug 7 – Sep 4 |
| Broccoli | Feb 26 – Mar 12 | Apr 9 – Apr 30 | — | Jul 24 – Aug 7 |
| Peas | — | — | Mar 12 – Apr 2 | Aug 7 – Aug 21 |
| Eggplant | Feb 12 – Feb 26 | May 7 – May 21 | — | — |
| Cabbage | Feb 26 – Mar 12 | Mar 26 – Apr 9 | — | Jul 24 – Aug 7 |
| Radish | — | — | Mar 19 – May 7 | Sep 4 – Oct 2 |
| Strawberry | — | Mar 26 – Apr 16 | — | — |
| Beets | — | — | Apr 2 – May 14 | Aug 7 – Aug 21 |
Nearby cities in Connecticut
- Stamford — zone 7a, last frost Apr 23, first frost Oct 16
- Bridgeport — zone 7a, last frost Apr 9, first frost Nov 1
- Danbury — zone 6b, last frost May 6, first frost Oct 7
- New Haven — zone 7a, last frost Apr 22, first frost Oct 20
- Waterbury — zone 6b, last frost May 1, first frost Oct 11
- Hartford — zone 6b, last frost Apr 23, first frost Oct 20
More: all Connecticut cities · other zone 7a cities: Louisville, KY, Wichita, KS, Cleveland, OH, Lexington, KY, St. Louis, MO, Boise, ID, Amarillo, TX, Providence, RI
Norwalk gardening questions
When is the last frost in Norwalk, CT?
Plan around Apr 23. At NOAA's Stamford 5 N, CT station, 7.0 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 Apr 17, and after May 2 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 3. The 90% and 10% dates are 29 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Norwalk, CT?
Start seeds indoors Feb 26 – Mar 12 and set transplants outside Apr 30 – May 14, once nights stay above 50°F and the soil is near 60°F. That leaves 176 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 Norwalk?
About 188 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 168 days, and in 1 year in 10 it runs 208 days or more. In fall there is a 10% chance of frost by Oct 8 and a 30% chance by Oct 16. That ranks 5th longest of 7 Connecticut cities on this site.
When should I plant a fall garden in Norwalk?
Count back from the first fall frost (Oct 16): transplant broccoli Jul 24 – Aug 7; sow kale Aug 7 – Sep 4; sow lettuce Aug 7 – Sep 4; sow radishes Sep 4 – Oct 2. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 2. How the math works: succession and fall planting.
Did Norwalk's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Norwalk is zone 7a on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
Is all of Norwalk in zone 7a?
No. Zone 7a covers about 90% of the city's land; the rest is in 7b (10%), measured across the city's 5 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.