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USDA Hardiness Zone 5b

Frost Dates for 03235 — Franklin, New Hampshire

NOAA 1991–2020 normals from Franklin Falls Dam, NH (450 ft), 2 miles north.

Updated

In Franklin, the last spring frost (32°F) is around May 7 in half of years and has passed by May 20 in nine years out of ten. The first fall frost comes around October 3, as early as September 24 one year in ten, leaving a typical freeze-free season of 148 days (NOAA, Franklin Falls Dam, NH).

Last spring frost
May 7

50% probability

First fall frost
October 3

50% probability

Growing season
148 days

freeze-free, 50%

Hardiness zone
5b

-15 to -10°F (-26.1 to -23.3°C) coldest night

First snow
December 2

median, 1991–2020

Last snow
March 31

median, 1991–2020

Winters with snow
100%

30 of 30 observed

Snow per year
61.9"

NOAA normal

Frost risk by date in Franklin

Half of springs at Franklin Falls Dam, NH see their last 32°F night by May 7; only one in ten is past it by April 27, and one in ten still has one after May 20. Planting tender crops after May 13 leaves a 30% risk of a frost on them, after May 16 20%, and after May 20 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 3 in half of years, as early as September 24 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 10 days later, around October 13; in spring the one-in-ten date for 28°F is May 7, 13 days before the 32°F one. The freeze-free season lasts 148 days in a typical year, shorter than at 49% of the 51 New Hampshire stations; it reaches 163 days one year in ten and falls short of 132 one year in ten. On average 174 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 13 days longer, to about May 20, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 20 and March 29.

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

Freeze probabilities 1991–2020 at Franklin Falls Dam, 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 03235 →Compare Franklin with another place →

Compared with the next station

The nearest other station, Salisbury, NH, 7 miles southwest of Franklin, has a last frost 7 days later (May 14), a first frost 4 days earlier (September 29), a season 10 days shorter.

Frost dates for 03303 (Boscawen) →

When it snows in Franklin, New Hampshire

The first measurable snow (0.1 inch or more) in Franklin usually arrives around December 2, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Lakeport 2, NH, 12.2 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 37 days after the last snow.

Planting calendar for 03235

What to do and when, from the 50% frost dates for Franklin, New Hampshire
WhenWhat to do
February 26 – March 12Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 12 – March 26Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 9 – April 23Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 7 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 11Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 19Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 3 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 03235 is 2 miles from Franklin Falls Dam, NH, which stands at 450 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 03276 (Tilton). The 2023 USDA Plant Hardiness Zone Map lists ZIP 03235 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°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 5b places in New Hampshire