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USDA Hardiness Zone 6a

Frost Dates for 03052 — Litchfield, New Hampshire

NOAA 1991–2020 normals from Nashua 2 NNW, NH (135 ft), 4 miles south.

Updated

In Litchfield, the last spring frost (32°F) is around April 30 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 12, as early as September 30 one year in ten, leaving a typical freeze-free season of 165 days (NOAA, Nashua 2 NNW, NH).

Last spring frost
April 30

50% probability

First fall frost
October 12

50% probability

Growing season
165 days

freeze-free, 50%

Hardiness zone
6a

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

First snow
December 3

median, 1991–2020

Last snow
March 25

median, 1991–2020

Winters with snow
100%

29 of 29 observed

Snow per year
52.9"

NOAA normal

Frost risk by date in Litchfield

Half of springs at Nashua 2 NNW, NH see their last 32°F night by April 30; only one in ten is past it by April 18, and one in ten still has one after May 11. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 6 20%, and after May 11 10%. The 11 days between the even-odds date and the one-in-ten date is the narrowest of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 12 in half of years, as early as September 30 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 12 days later, around October 24; in spring the one-in-ten date for 28°F is April 29, 12 days before the 32°F one. The freeze-free season lasts 165 days in a typical year, longer than at 90% of the 51 New Hampshire stations; it reaches 185 days one year in ten and falls short of 148 one year in ten. On average 155 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 10, and return around October 2. Severe cold of 16°F or below comes every winter, usually between December 1 and March 16.

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

Freeze probabilities 1991–2020 at Nashua 2 NNW, 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 03052 →Compare Litchfield with another place →

Weather by month in Litchfield

July is the warmest month at Nashua 2 NNW, NH, averaging 84°F by day and 61°F at night; January is the coldest at 34°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 44% of years.

Warmth for growing adds up to 2,723 growing degree days a year (base 50°F), more than at 92% of the 51 New Hampshire stations. 31% of them (842) have built up by the end of June, and July adds the most, 704. Precipitation totals 48.2 inches a year, most in October (4.8") and least in February (3.2"); May to September bring 41% of it.

Monthly normals 1991–2020 at Nashua 2 NNW, NH
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan34143.4100%300
Feb37153.2100%270
Mar45234.3100%267
Apr59344.2100%1460
May70463.944%1262
Jun78564.30%0513
Jul84613.70%0704
Aug83593.90%0649
Sep75514.111%<1400
Oct63394.892%8110
Nov51303.9100%2116
Dec40214.5100%281

Monthly normals 1991–2020 at Nashua 2 NNW, NH (135 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, Hudson 1 SSE, NH, 5 miles southeast of Litchfield, has a last frost 3 days later (May 3), a first frost 4 days earlier (October 8), a season 9 days shorter.

Frost dates for 03051 (Hudson) →

When it snows in Litchfield, New Hampshire

The first measurable snow (0.1 inch or more) in Litchfield usually arrives around December 3, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Nashua 2 NNW, NH, 4.2 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 36 days after the last snow.

Planting calendar for 03052

What to do and when, from the 50% frost dates for Litchfield, New Hampshire
WhenWhat to do
February 19 – March 5Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 5 – March 19Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 2 – April 16Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 30 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 20Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 28Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 12 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 03052 is 4 miles from Nashua 2 NNW, NH, which stands at 135 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 03054 (Merrimack). The 2023 USDA Plant Hardiness Zone Map lists ZIP 03052 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