USDA zones 6b, 7a in Rhode Island
USDA plant hardiness zones 6b, 7a cover 8 locations across Rhode Island (average annual extreme minimum −5 to 5 °F): Ashaway, RI, Greene, RI, Greene, RI, Newport, RI, Warwick, RI, Warwick, RI, and 2 more. Average last spring frost across this state ranges April 11 (Ashaway) to May 3 (Warwick), and growing seasons run 159–206 days (Greene to Newport) — even within one state, because hardiness sets winter survival, not planting dates. Here all 2 of its hardiness zones share this page rather than sit on 2 thin ones. The table below gives every Rhode Island location's own frost dates; the printable planting calendar uses Warwick, this state's median-season location.
- USDA zones
- 6b, 7a−5 to 5 °F
- Last frost range
- Apr 11–May 3avg, 32°F
- First frost range
- Oct 8–Nov 4avg, 32°F
- Growing season range
- 159–206days
Locations in this group
Every location below keeps its own USDA zone, weather station, and frost dates — they are listed together here, not averaged. Find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Zone | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|---|
| Ashaway | 6b | — | Westerly State Ap | Apr 11 | Oct 31 | 201 |
| Greene | 6b | Greenville, Chepachet, Pascoag, Putnam, East Douglas, Harmony, +8 more | N Foster 1 E | Apr 25 | Oct 19 | 176 |
| Greene | 6b | Hope Valley, Hopkinton, Carolina, Kingston, Wyoming | Kingston | May 3 | Oct 8 | 159 |
| Newport | 7a | Newport East, Melville, Bliss Corner | Newport State Ap | Apr 11 | Nov 4 | 206 |
| Warwick | 6b | Cranston, Providence, Greene, Greenville | Providence T F Green Ap | Apr 11 | Oct 30 | 199 |
| Warwick | 7a | Wakefield-Peace Dale, Narragansett Pier, Carolina, Charlestown, Kingston | Kingston | May 3 | Oct 8 | 159 |
| Warwick * | 7a | Cranston, Providence, East Providence, Pawtucket, Tiverton, North Seekonk, +1 more | Providence T F Green Ap | Apr 11 | Oct 30 | 199 |
| Westerly | 7a | Pawcatuck, Bradford | Westerly State Ap | Apr 11 | Oct 31 | 201 |
* Warwick is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Warwick, representative)
Computed from Warwick's average frost dates — the median-season location in this Rhode Islandzones 6b, 7a group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Feb 14 – Feb 28 | Apr 18 – Apr 25 | Jun 17 – Jul 7 | — | matures comfortably |
| Pepper | Very tender | Jan 31 – Feb 14 | Apr 25 – May 2 | Jun 24 – Jul 24 | — | matures comfortably |
| Cucumber | Tender | Mar 14 – Mar 21 | Apr 18 – Apr 25 | Jun 7 – Jun 27 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 18 – Apr 25 | Jun 2 – Jun 17 | — | matures comfortably |
| Bush bean | Tender | — | Apr 18 – Apr 25 | Jun 7 – Jun 17 | Aug 31 – Sep 10 | matures comfortably |
| Sweet corn | Tender | — | Apr 11 – Apr 25 | Jun 10 – Jul 10 | — | matures comfortably |
| Basil | Very tender | Feb 28 – Mar 14 | Apr 18 – Apr 25 | May 18 – Jun 2 | — | matures comfortably |
| Lettuce | Half-hardy | Feb 28 – Mar 14 | Mar 14 – Mar 28 | Apr 28 – May 13 | Aug 17 – Sep 1 | matures comfortably |
| Pea | Hardy | — | Feb 28 – Mar 14 | Apr 24 – May 9 | Aug 7 – Aug 22 | matures comfortably |
| Spinach | Hardy | — | Feb 28 – Mar 14 | Apr 9 – Apr 19 | Aug 27 – Sep 6 | matures comfortably |
| Carrot | Half-hardy | — | Mar 21 – Mar 28 | May 20 – Jun 9 | Jul 28 – Aug 17 | matures comfortably |
| Broccoli | Half-hardy | Feb 14 – Feb 28 | Mar 14 – Mar 28 | May 8 – May 28 | Aug 2 – Aug 22 | matures comfortably |
Which crops fit this growing season
Using Warwick's own 199-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Warwick)
From NOAA's 1991–2020 Climate Normals at station USW00014765. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Apr 26 | May 7 | Oct 18 | Nov 1 | 175 |
| 32°F (freeze) | Apr 11 | Apr 23 | Oct 30 | Nov 12 | 199 |
| 28°F | Apr 1 | Apr 11 | Nov 9 | Nov 26 | 221 |
| 24°F | Mar 21 | Apr 3 | Nov 22 | Dec 8 | 245 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 8 locations is 2,936; Warwick's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 3,090 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 5,395 | cool-season crops (brassicas, greens) |
Hardiness zones 6b, 7a in Rhode Island
Rhode Island's 2 hardiness zones (6b, 7a) — an average annual extreme minimum winter temperature range of −5 to 5 °F on the USDA's 2023 map — share this page Rhode Island is small enough that every one of its hardiness zones (6b, 7a) is combined onto this one page rather than split thin across several. Each location's own zone is in the table above. Hardiness sets winter survival, not planting dates; the frost calendar uses Warwick, this page's representative location.
See all USDA hardiness zones across the site, or browse all Rhode Island locations.
Frequently asked questions
- What USDA hardiness zones does Rhode Island have?
- Rhode Island spans zones 6b, 7a — an average annual extreme minimum winter temperature range of −5 to 5 °F on the USDA's 2023 map — across 8 locations, each listed with its own zone in the table above. The zone does not set planting dates; see the frost calendar for that.
- Where in Rhode Island is the growing season longest?
- Newport runs the longest season on this page at about 206 days; Greene is shortest at about 159 days — hardiness zone is not what separates them, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Rhode Island?
- Using Warwick's frost dates (this page's median-season location): start seeds indoors about Feb 14 – Feb 28, then transplant outside about Apr 18 – Apr 25. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Rhode Island have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 8 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.