Boston frost dates and planting season

Name: Boston
Address: Massachusetts, United States

When to plant vegetables here. Cover calendars (fleece, cold frame, unheated greenhouse) are on each plant’s when-to-plant page.

Boston has a moderate growing season, with roughly 187 frost-free days between the typical frost dates. Typical last spring frost: around April 25 (half of years later). Typical first fall frost: around October 30. Plant cool-season crops after about April 13; wait until about May 11 for warm-season crops.

Frost-free days187Apr 25 – Oct 30

Frost-free season in Boston. Based on average frost dates. Adjust a week or two for your conditions.

Cover calendars (fleece, cold frame, unheated greenhouse) live on each crop’s when-to-plant page.

Weekly possible temperature−12 – 97 °F

Frost-free days187

Typical last spring frostApril 25

Typical first fall frostOctober 30

Days suitable for warm-season vegetables154 (May 11 – October 11)

Days suitable for cool-season vegetables168 (April 13 – July 5; August 17 – November 8)

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

Frost dates calculated by Plan & Plant from Weather data by Open-Meteo.com (CC BY 4.0). Local frost pockets, valleys and coastal sites can differ by 1–3 weeks.

How we calculated this

Data: ERA5-Land via Open-Meteo, cell 42.40, -71.10, years 2019–2026 (not a 30-year climate normal yet).
Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-6).

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What to plant when

Cool-season vegetables

Earliest outdoor start: April 13

Suitable window: April 13 – July 5; August 17 – November 8

Cool-season crops prefer cooler weather.

Midsummer is often too hot, so suitable weeks split into more than one window.

See cool-season details

Warm-season vegetables

Earliest outdoor start: May 11

Suitable window: May 11 – October 11

Warm-season crops need mild or warm weather and cannot take frost.

Frost kills these crops, and cold snaps set them back.

See warm-season details

Green = usually good weeks to grow; blue or gray = usually too cold for that crop type.

Starter plants for Boston

Cool-season

Radish Sow: March 14 – June 28; August 26 – September 10 Planting dates
Arugula Sow: March 14 – June 28 Planting dates
Spinach Sow: March 14 – June 28 Planting dates
Lettuce Sow: March 14 – June 28 Planting dates
Kale Sow: March 14 – May 8 Planting dates
Beet Sow: March 28 – August 1 Planting dates

Warm-season

Zucchini Sow: May 28 – July 19 Planting dates
Cucumber Sow: May 28 – July 14 Planting dates
Green bean Sow: May 23 – July 23 Planting dates
Tomato Transplant: May 23 – June 24 Start indoors, then transplant. Planting dates
Bell pepper Transplant: May 28 – June 19 Start indoors, then transplant. Planting dates

How these dates are judged

Last frost: The typical last spring date when frost is still expected.
First frost: The typical first fall date when frost returns.
Frost-free days: The approximate days between those two dates.
Cool-season vegetables: Crops that prefer cooler weather, such as lettuce, kale, peas, and radish.
Warm-season vegetables: Crops that need warm weather and cannot take frost, such as tomato, pepper, squash, and beans.

Cool-season planting window

Apr 13 – Jul 5; Aug 17 – Nov 8 (168 days)

Warm-season planting window

May 11 – Oct 11 (154 days)

Usually too cold

January 1 – April 12
November 9 – December 31

Weekly temperatures and planting windows

Temperatures across the year for Boston, with cool- and warm-season weeks and frost dates.

Possible min to max
Average min to max
Suitable
Tolerable
Too cold
Too hot

Selected week · tap a week or use the arrows

Week 16 · Apr 13 – Apr 19

Average 42 to 58 °F · Possible 31 to 83 °F

Cool season: tolerable

Warm season: too cold

A week is suitable for a crop type when its average low and high sit inside that type's range and its possible readings stay within the frost and heat limits (cool: 28 °F to 81 °F, warm: 32 °F to 90 °F); crossing a limit makes it tolerable, and for warm crops any chance of frost makes it too cold.

Based on average frost dates.

Massachusetts, United States · 42.40001, -71.1 · 2026

Coldest weekly possible temperature−12 °F

Hottest weekly possible temperature97 °F

Last expected spring frostApril 25

First expected fall frostOctober 30

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