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USDA Hardiness Zone 6b

Frost Dates for 02324 — Bridgewater, Massachusetts

NOAA 1991–2020 normals from Bridgewater, MA (40 ft), 2 miles southeast.

Updated

In Bridgewater, the last spring frost (32°F) is around May 1 in half of years and has passed by May 15 in nine years out of ten. The first fall frost comes around October 9, as early as September 26 one year in ten, leaving a typical freeze-free season of 161 days (NOAA, Bridgewater, MA).

Last spring frost
May 1

50% probability

First fall frost
October 9

50% probability

Growing season
161 days

freeze-free, 50%

Hardiness zone
6b

-5 to 0°F (-20.6 to -17.8°C) coldest night

First snow
December 17

median, 1991–2020

Last snow
March 15

median, 1991–2020

Winters with snow
100%

16 of 16 observed

Snow per year
25.7"

NOAA normal

Frost risk by date in Bridgewater

Half of springs at Bridgewater, MA see their last 32°F night by May 1; only one in ten is past it by April 20, and one in ten still has one after May 15. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 10 20%, and after May 15 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 51% of the 71 Massachusetts stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 9 in half of years, as early as September 26 one year in ten, and holds off past October 25 one year in ten. A hard freeze of 28°F follows 15 days later, around October 24; in spring the one-in-ten date for 28°F is May 3, 12 days before the 32°F one. The freeze-free season lasts 161 days in a typical year, shorter than at 73% of the 71 Massachusetts stations; it reaches 181 days one year in ten and falls short of 141 one year in ten. On average 142 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 12, and return around September 29. Severe cold of 16°F or below comes every winter, usually between December 3 and March 12.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 29May 3May 6May 9May 12May 16May 19May 23May 28
32°FApr 20Apr 23Apr 26Apr 29May 1May 3May 6May 10May 15
28°FApr 3Apr 8Apr 12Apr 15Apr 18Apr 20Apr 23Apr 26May 3
24°FMar 20Mar 25Mar 30Apr 1Apr 3Apr 4Apr 7Apr 11Apr 15
20°FMar 8Mar 13Mar 15Mar 19Mar 22Mar 26Mar 30Apr 1Apr 4
16°FFeb 26Mar 2Mar 6Mar 9Mar 12Mar 15Mar 18Mar 22Mar 27
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 17Sep 20Sep 24Sep 27Sep 29Oct 1Oct 4Oct 7Oct 12
32°FSep 26Oct 1Oct 3Oct 6Oct 9Oct 12Oct 16Oct 20Oct 25
28°FOct 8Oct 13Oct 18Oct 22Oct 24Oct 28Oct 31Nov 3Nov 6
24°FOct 23Oct 28Nov 1Nov 3Nov 5Nov 8Nov 12Nov 15Nov 22
20°FNov 4Nov 9Nov 13Nov 16Nov 19Nov 22Nov 27Dec 1Dec 6
16°FNov 16Nov 22Nov 27Dec 1Dec 3Dec 6Dec 11Dec 16Dec 23

Freeze probabilities 1991–2020 at Bridgewater, MA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 02324 →Compare Bridgewater with another place →

Weather by month in Bridgewater

July is the warmest month at Bridgewater, MA, averaging 83°F by day and 60°F at night; January is the coldest at 38°F and 17°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 51% of years.

Warmth for growing adds up to 2,522 growing degree days a year (base 50°F), fewer than at 69% of the 71 Massachusetts stations. 29% of them (738) have built up by the end of June, and July adds the most, 662. Precipitation totals 51.2 inches a year, most in March (5.2") and least in August (2.7"); May to September bring 37% of it.

Monthly normals 1991–2020 at Bridgewater, MA
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan38174.2100%290
Feb40183.4100%261
Mar47265.2100%2310
Apr58354.8100%1251
May68453.851%1219
Jun77544.10%0457
Jul83604.30%0662
Aug81582.70%0601
Sep74504.318%1370
Oct63405.196%6123
Nov53314.6100%1924
Dec43244.7100%263

Monthly normals 1991–2020 at Bridgewater, MA (40 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Brockton, MA, 5 miles north of Bridgewater, has a last frost 9 days earlier (April 22), a first frost 10 days later (October 19), a season 17 days longer.

Frost dates for 02301 (Brockton) →

When it snows in Bridgewater, Massachusetts

The first measurable snow (0.1 inch or more) in Bridgewater usually arrives around December 17, and the last of the season around March 15. Those are the middle dates across the winters of 1991–2020 at Taunton, MA, 7.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 47 days after the last snow.

Planting calendar for 02324

What to do and when, from the 50% frost dates for Bridgewater, Massachusetts
WhenWhat to do
February 20 – March 6Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 6 – March 20Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 3 – April 17Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 1 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 17Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 25Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 9 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 02324 is 2 miles from Bridgewater, MA, which stands at 40 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 02324 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Massachusetts →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

ZIP codes measured at the same station

Other zone 6b places in Massachusetts