Frost Dates for Willimantic, CT 06226
Last spring frost April 27 · First fall frost October 11 · 167 frost-free days · USDA Zone 6b
ZIP 06226 has about 19,300 people.
Moderate season: 167 frost-free days. Spring frost risk spans April 13–May 10 (27 days). Fall frost risk spans September 29–October 22 (23 days).
Frost probability for 06226
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 10 | April 27 | April 13 |
| Fall (first frost) | September 29 | October 11 | October 22 |
Dates come from NOAA 1971–2000 freeze probabilities at NORWICH PUBLIC UTILITY PLT (23.4 km away); the 50% date is the median year.
Which crops fit a 167-day season in Willimantic
In Willimantic (167 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 23 | May 11–May 18 | 125 | fits: 80 days to maturity, 125 available after May 11. | Jun 11 |
| Pepper | Mar 16 | May 11–May 18 | 125 | fits: 75 days to maturity, 125 available after May 11. | Jun 16 |
| Lettuce | Mar 2 | Mar 30–Apr 6 | 202 | two-plantings: Plant Mar 30 and again by Aug 20; both mature before Oct 18. | Aug 20 |
| Carrots | — | Apr 6–Apr 13 | 209 | fits: 70 days to maturity, 209 available after Apr 6. | Aug 9 |
| Cucumber | Apr 6 | May 11–May 18 | 139 | two-plantings: Plant May 11 and again by Jul 15; both mature before Sep 27. | Jul 15 |
| Beans | — | May 4–May 18 | 153 | two-plantings: Plant May 4 and again by Jul 22; both mature before Oct 4. | Jul 22 |
| Peas | — | Mar 2–May 11 | 230 | fits: 65 days to maturity, 230 available after Mar 2. | Jul 31 |
| Zucchini | Apr 13 | May 11–May 18 | 139 | two-plantings: Plant May 11 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Onion | Feb 2 | Mar 30–Apr 13 | 202 | fits: 100 days to maturity, 202 available after Mar 30. | — |
| Spinach | — | Mar 2–Apr 20 | 244 | two-plantings: Plant Mar 2 and again by Sep 8; both mature before Nov 1. | Sep 8 |
| Kale | Feb 16 | Mar 30–Apr 13 | 216 | two-plantings: Plant Mar 30 and again by Aug 24; both mature before Nov 1. | Aug 24 |
| Broccoli | Mar 2 | Mar 30–Apr 13 | 202 | fits: 80 days to maturity, 202 available after Mar 30. | Jul 16 |
| Cabbage | Mar 2 | Mar 30–Apr 13 | 216 | fits: 70 days to maturity, 216 available after Mar 30. | Aug 9 |
| Radish | — | Mar 2–May 25 | 230 | two-plantings: Plant Mar 2 and again by Sep 9; both mature before Oct 18. | Sep 9 |
| Beets | — | Mar 2–May 25 | 230 | two-plantings: Plant Mar 2 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Potatoes | — | Apr 13–Apr 20 | 188 | fits: 90 days to maturity, 188 available after Apr 13. | — |
| Garlic | — | Oct 11 | 272 | overwinter: Plant Oct 11 to Nov 1; harvest the following summer. | Nov 1 |
| Strawberry | — | Mar 23–May 18 | 223 | perennial: A perennial: plant Mar 23; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 30 | May 4–May 11 | 139 | fits: 75 days to maturity, 139 available after May 4. | Jun 23 |
| Pumpkin | Apr 13 | May 11–May 11 | 132 | fits: 100 days to maturity, 132 available after May 11. | May 29 |
| Cauliflower | Mar 16 | Apr 20–May 4 | 181 | fits: 75 days to maturity, 181 available after Apr 20. | Jul 21 |
| Swiss Chard | Mar 2 | Apr 13–Apr 13 | 188 | two-plantings: Plant Apr 13 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Arugula | — | Mar 2–May 25 | 244 | two-plantings: Plant Mar 2 and again by Sep 8; both mature before Nov 1. | Sep 8 |
| Brussel Sprouts | Mar 2 | Mar 30–Apr 13 | 216 | fits: 100 days to maturity, 216 available after Mar 30. | Jul 10 |
| Butternut Squash | Apr 13 | May 11–May 18 | 132 | fits: 100 days to maturity, 132 available after May 11. | May 29 |
| Eggplant | Mar 9 | May 11–May 18 | 125 | fits: 70 days to maturity, 125 available after May 11. | Jun 21 |
| Okra | Mar 30 | May 4–May 11 | 146 | two-plantings: Plant May 4 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Basil | Mar 23 | May 18–May 18 | 132 | fits: 60 days to maturity, 132 available after May 18. | Jul 15 |
| Cilantro | — | Mar 30–Apr 20 | 202 | two-plantings: Plant Mar 30 and again by Aug 15; both mature before Oct 18. | Aug 15 |
| Parsley | Feb 16 | May 4–May 11 | 167 | fits: 70 days to maturity, 167 available after May 4. | Jul 26 |
| Celery | Feb 16 | May 4–May 18 | 167 | fits: 120 days to maturity, 167 available after May 4. | Jun 6 |
| Scallions | Feb 16 | Mar 30–Apr 13 | 216 | two-plantings: Plant Mar 30 and again by Aug 19; both mature before Nov 1. | Aug 19 |
| Turnip | — | Mar 30–Apr 13 | 216 | two-plantings: Plant Mar 30 and again by Aug 29; both mature before Nov 1. | Aug 29 |
| Kohlrabi | — | Mar 16–Mar 30 | 230 | two-plantings: Plant Mar 16 and again by Aug 24; both mature before Nov 1. | Aug 24 |
| Bok Choy | Mar 30 | Apr 20–Apr 27 | 181 | two-plantings: Plant Apr 20 and again by Aug 20; both mature before Oct 18. | Aug 20 |
| Collards | Feb 16 | Mar 30–Apr 13 | 216 | two-plantings: Plant Mar 30 and again by Aug 19; both mature before Nov 1. | Aug 19 |
| Cantaloupe | Apr 13 | May 11–May 18 | 125 | fits: 85 days to maturity, 125 available after May 11. | Jun 6 |
| Chives | Feb 2 | May 4–May 11 | 181 | fits: 90 days to maturity, 181 available after May 4. | — |
| Dill | — | Mar 2–May 25 | 230 | two-plantings: Plant Mar 2 and again by Aug 10; both mature before Oct 18. | Aug 10 |
| Oregano | Feb 16 | May 4–May 11 | 181 | fits: 80 days to maturity, 181 available after May 4. | — |
| Rosemary | Feb 2 | May 4–May 11 | 167 | fits: 80 days to maturity, 167 available after May 4. | — |
| Sage | Mar 2 | May 4–May 11 | 181 | fits: 75 days to maturity, 181 available after May 4. | — |
| Thyme | Feb 16 | May 4–May 11 | 181 | fits: 90 days to maturity, 181 available after May 4. | — |
| Calendula | Mar 16 | Apr 13–Apr 27 | 188 | two-plantings: Plant Apr 13 and again by Aug 15; both mature before Oct 18. | Aug 15 |
| Cosmos | Mar 30 | Apr 27–May 11 | 153 | two-plantings: Plant Apr 27 and again by Jul 15; both mature before Sep 27. | Jul 15 |
| Lavender | Feb 2 | Apr 27–May 11 | 188 | fits: 90 days to maturity, 188 available after Apr 27. | — |
| Marigolds | Mar 16 | Apr 27–May 4 | 153 | two-plantings: Plant Apr 27 and again by Jul 25; both mature before Sep 27. | Jul 25 |
| Melons | Apr 13 | May 11–May 18 | 125 | fits: 85 days to maturity, 125 available after May 11. | Jun 6 |
| Mint | — | Apr 27–May 11 | 188 | fits: 90 days to maturity, 188 available after Apr 27. | — |
| Nasturtiums | Mar 30 | Apr 27–May 4 | 153 | two-plantings: Plant Apr 27 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Pole Beans | — | May 4–May 18 | 146 | fits: 65 days to maturity, 146 available after May 4. | Jul 10 |
| Spaghetti Squash | Apr 13 | May 11–May 18 | 132 | fits: 90 days to maturity, 132 available after May 11. | Jun 8 |
| Sunflowers | — | Apr 27–May 11 | 153 | fits: 70 days to maturity, 153 available after Apr 27. | Jul 5 |
| Tomatillos | Mar 2 | May 4–May 11 | 132 | fits: 75 days to maturity, 132 available after May 4. | Jun 16 |
| Watermelon | Apr 13 | May 4–May 11 | 132 | fits: 80 days to maturity, 132 available after May 4. | Jun 11 |
| Yellow Squash | Apr 13 | May 11–May 18 | 139 | two-plantings: Plant May 11 and again by Jul 20; both mature before Sep 27. | Jul 20 |
| Zinnias | Mar 30 | Apr 27–May 11 | 153 | two-plantings: Plant Apr 27 and again by Jul 15; both mature before Sep 27. | Jul 15 |
Month by month in Willimantic
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 2), Lavender (Feb 2), Onion (Feb 2), Rosemary (Feb 2), Celery (Feb 16), Collards (Feb 16), +5 more. |
| March | Start indoors: Broccoli (Mar 2), Brussel Sprouts (Mar 2), Cabbage (Mar 2), Lettuce (Mar 2), Sage (Mar 2), Swiss Chard (Mar 2), +14 more. Direct sow from: Arugula (Mar 2), Beets (Mar 2), Dill (Mar 2), Peas (Mar 2), Radish (Mar 2), Spinach (Mar 2), +3 more. Transplant from: Broccoli (Mar 30), Brussel Sprouts (Mar 30), Cabbage (Mar 30), Collards (Mar 30), Kale (Mar 30), Lettuce (Mar 30), +2 more. Plant: Strawberry (Mar 23). |
| April | Start indoors: Cucumber (Apr 6), Butternut Squash (Apr 13), Cantaloupe (Apr 13), Melons (Apr 13), Pumpkin (Apr 13), Spaghetti Squash (Apr 13), +3 more. Direct sow from: Carrots (Apr 6), Potatoes (Apr 13), Sunflowers (Apr 27). Transplant from: Calendula (Apr 13), Swiss Chard (Apr 13), Bok Choy (Apr 20), Cauliflower (Apr 20), Cosmos (Apr 27), Lavender (Apr 27), +4 more. Last frost around April 27. |
| May | Direct sow from: Beans (May 4), Pole Beans (May 4). Transplant from: Celery (May 4), Chives (May 4), Corn (May 4), Okra (May 4), Oregano (May 4), Parsley (May 4), +17 more. Last sowing dates: Butternut Squash (May 29), Pumpkin (May 29). |
| June | Last sowing dates: Cantaloupe (Jun 6), Celery (Jun 6), Melons (Jun 6), Spaghetti Squash (Jun 8), Tomato (Jun 11), Watermelon (Jun 11), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 5), Brussel Sprouts (Jul 10), Pole Beans (Jul 10), Basil (Jul 15), Cosmos (Jul 15), Cucumber (Jul 15), +11 more. |
| August | Last sowing dates: Cabbage (Aug 9), Carrots (Aug 9), Beets (Aug 10), Dill (Aug 10), Swiss Chard (Aug 10), Calendula (Aug 15), +8 more. |
| September | Last sowing dates: Arugula (Sep 8), Spinach (Sep 8), Radish (Sep 9). |
| October | Direct sow from: Garlic (Oct 11). First frost around October 11. |
| November | Last sowing dates: Garlic (Nov 1). |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Willimantic, CT (ZIP 06226)?
The median last spring frost date for Willimantic, CT (ZIP code 06226) is around April 27. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 13; one in ten it runs past May 10.
What is the first fall frost date in Willimantic, CT?
The median first fall frost date for Willimantic, CT is around October 11. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 29 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Willimantic, CT?
The frost-free growing season in Willimantic is about 167 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Willimantic (167 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Willimantic, CT?
Willimantic, CT is in USDA hardiness zone 6b (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Willimantic, CT?
Start tomatoes indoors Mar 23 and plant out May 11 in Willimantic. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Willimantic?
Two: plant Mar 30 and again by Aug 20; both mature before Oct 18.
When do I plant garlic in Willimantic?
Oct 11 to Nov 1; it overwinters and is ready the following summer.
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