Cranston, Rhode Island: planting zone & frost dates
Cranston is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around Apr 17 and the first fall frost around Oct 24.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 23 | Oct 16 |
| Typical planning date (30% risk) | Apr 17 | Oct 24 |
| Median (50%) | Apr 11 | Oct 30 |
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 PROVIDENCE T F GREEN AP, RI (USW00014765), 4.3 mi (6.9 km) from the city center and 138 ft lower than the city center (-42 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Cranston
Cranston spans more than one half-zone. Share of the city's land area by zone (via its 6 ZIP codes): 6b (52%), 7a (48%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Cranston
Dates are counted from the 30%-risk frost dates above (last frost Apr 17, first frost Oct 24). 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 20 – Mar 6 | Apr 24 – May 8 | — | — |
| Pepper | Feb 6 – Feb 20 | May 1 – May 15 | — | — |
| Lettuce | Mar 6 – Mar 20 | Apr 3 – Apr 24 | Mar 20 – May 1 | Aug 15 – Sep 12 |
| Green Beans | — | — | Apr 24 – May 29 | Aug 1 – Aug 15 |
| Sweet Corn | — | — | Apr 24 – May 22 | — |
| Zucchini & Summer Squash | Mar 20 – Mar 27 | Apr 24 – May 8 | Apr 24 – May 15 | Aug 1 – Aug 15 |
| Cucumber | Mar 20 – Mar 27 | May 1 – May 8 | Apr 24 – May 15 | Aug 1 – Aug 15 |
| Carrot | — | — | Mar 27 – May 1 | Aug 1 – Aug 15 |
| Onion | Jan 23 – Feb 6 | Mar 20 – Apr 3 | — | — |
| Potato | — | Mar 20 – Apr 10 | — | — |
| Basil | Mar 6 – Mar 20 | May 1 – May 15 | May 1 – May 22 | — |
| Spinach | — | — | Mar 6 – Apr 3 | Aug 29 – Sep 26 |
| Kale | Feb 20 – Mar 6 | Mar 20 – Apr 10 | Mar 20 – Apr 10 | Aug 15 – Sep 12 |
| Broccoli | Feb 20 – Mar 6 | Apr 3 – Apr 24 | — | Aug 1 – Aug 15 |
| Peas | — | — | Mar 6 – Mar 27 | Aug 15 – Aug 29 |
| Eggplant | Feb 6 – Feb 20 | May 1 – May 15 | — | — |
| Cabbage | Feb 20 – Mar 6 | Mar 20 – Apr 3 | — | Aug 1 – Aug 15 |
| Radish | — | — | Mar 13 – May 1 | Sep 12 – Oct 10 |
| Strawberry | — | Mar 20 – Apr 10 | — | — |
| Beets | — | — | Mar 27 – May 8 | Aug 15 – Aug 29 |
Nearby cities in Rhode Island
- Providence — zone 7a, last frost Apr 17, first frost Oct 24
- Warwick — zone 7a, last frost Apr 17, first frost Oct 24
- Pawtucket — zone 7a, last frost Apr 28, first frost Oct 12
More: all Rhode Island cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Cranston gardening questions
When is the last frost in Cranston, RI?
Plan around Apr 17. At NOAA's Providence T F Green Airport, RI station, 4.3 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 11, and after Apr 23 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 1. The last frost is fairly predictable here: only 22 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Cranston, RI?
Start seeds indoors Feb 20 – Mar 6 and set transplants outside Apr 24 – May 8, once nights stay above 50°F and the soil is near 60°F. That leaves 190 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 Cranston?
About 199 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 183 days, and in 1 year in 10 it runs 216 days or more. In fall there is a 10% chance of frost by Oct 16 and a 30% chance by Oct 24. That ranks 2nd longest of 4 Rhode Island cities on this site.
When should I plant a fall garden in Cranston?
Count back from the first fall frost (Oct 24): transplant broccoli Aug 1 – Aug 15; sow kale Aug 15 – Sep 12; sow lettuce Aug 15 – Sep 12; sow radishes Sep 12 – Oct 10. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 9. How the math works: succession and fall planting.
Did Cranston's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Cranston is zone 6b 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 Cranston in zone 6b?
No. Zone 6b covers about 52% of the city's land; the rest is in 7a (48%), measured across the city's 6 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.