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USDA Hardiness Zone 6a

Frost Dates for 03055 — Milford, New Hampshire

NOAA 1991–2020 normals from Milford, NH (320 ft), 1 miles northeast.

Updated

In Milford, the last spring frost (32°F) is around May 3 in half of years and has passed by May 15 in nine years out of ten. The first fall frost comes around October 5, as early as September 25 one year in ten, leaving a typical freeze-free season of 156 days (NOAA, Milford, NH).

Last spring frost
May 3

50% probability

First fall frost
October 5

50% probability

Growing season
156 days

freeze-free, 50%

Hardiness zone
6a

-10 to -5°F (-23.3 to -20.6°C) coldest night

First snow
November 25

median, 1991–2020

Last snow
March 26

median, 1991–2020

Winters with snow
100%

18 of 18 observed

Snow per year
57.4"

NOAA normal

Frost risk by date in Milford

Half of springs at Milford, NH see their last 32°F night by May 3; only one in ten is past it by April 22, and one in ten still has one after May 15. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 10 20%, and after May 15 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 25 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 11 days later, around October 16; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 156 days in a typical year, longer than at 65% of the 51 New Hampshire stations; it reaches 173 days one year in ten and falls short of 138 one year in ten. On average 159 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 10 days longer, to about May 13, and return around September 28. Severe cold of 16°F or below comes every winter, usually between November 22 and March 20.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FMay 2May 6May 8May 11May 13May 16May 19May 21May 25
32°FApr 22Apr 26Apr 28May 1May 3May 5May 7May 10May 15
28°FApr 7Apr 11Apr 15Apr 17Apr 20Apr 22Apr 25Apr 28May 2
24°FMar 28Apr 1Apr 2Apr 4Apr 6Apr 9Apr 12Apr 16Apr 19
20°FMar 13Mar 19Mar 22Mar 26Mar 30Mar 31Apr 2Apr 4Apr 8
16°FMar 6Mar 10Mar 13Mar 17Mar 20Mar 23Mar 26Mar 30Apr 1
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 16Sep 20Sep 24Sep 26Sep 28Oct 1Oct 2Oct 4Oct 7
32°FSep 25Sep 29Oct 1Oct 3Oct 5Oct 8Oct 10Oct 13Oct 18
28°FOct 3Oct 7Oct 10Oct 14Oct 16Oct 19Oct 23Oct 27Nov 1
24°FOct 13Oct 18Oct 22Oct 26Oct 29Oct 31Nov 2Nov 6Nov 11
20°FOct 27Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 20Nov 25
16°FNov 8Nov 12Nov 16Nov 20Nov 22Nov 26Nov 29Dec 3Dec 9

Freeze probabilities 1991–2020 at Milford, NH, 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 03055 →Compare Milford with another place →

Weather by month in Milford

July is the warmest month at Milford, NH, averaging 83°F by day and 60°F at night; January is the coldest at 33°F and 14°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 60% of years.

Warmth for growing adds up to 2,495 growing degree days a year (base 50°F), more than at 78% of the 51 New Hampshire stations. 31% of them (781) have built up by the end of June, and July adds the most, 674. Precipitation totals 46.1 inches a year, most in October (4.9") and least in January (3.0"); May to September bring 41% of it.

Monthly normals 1991–2020 at Milford, NH
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan33143.0100%301
Feb36153.0100%270
Mar45243.8100%273
Apr58344.2100%1457
May69453.460%2234
Jun78554.00%0485
Jul83603.70%0674
Aug81583.70%0601
Sep73504.024%1346
Oct60384.9100%1080
Nov49283.9100%2012
Dec38204.5100%281

Monthly normals 1991–2020 at Milford, NH (320 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, E Milford, NH, 2 miles east of Milford, has a last frost 5 days earlier (April 28), a first frost 3 days later (October 8), a season 5 days longer.

Frost dates for 03031 (Amherst) →

When it snows in Milford, New Hampshire

The first measurable snow (0.1 inch or more) in Milford usually arrives around November 25, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Milford, NH, 1.1 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 38 days after the last snow.

Planting calendar for 03055

What to do and when, from the 50% frost dates for Milford, New Hampshire
WhenWhat to do
February 22 – March 8Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 8 – March 22Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 5 – April 19Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 3 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 13Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 21Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 5 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 03055 is 1 mile from Milford, NH, which stands at 320 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03055 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across New Hampshire →

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 6a places in New Hampshire