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Frost Dates and Planting Windows in New Hampshire

The 32°F frost dates at the 54 weather stations in New Hampshire with NOAA's 1991–2020 Climate Normals, and the planting windows they give. These are long-term statistics, not a forecast. For the dates at the station nearest you, enter your ZIP code.

The planner uses the weather station nearest your ZIP code.

Frost dates across New Hampshire

Each risk level uses a date with a set chance of frost. In spring, it's the chance of a 32°F frost on or after the last-frost date. In fall, it's the chance of the first 32°F frost on or before the first-frost date. At the Typical level (30%), the last frost ranges from April 27 to June 4 across the state, and the first frost from September 13 to October 13.

32°F frost dates: earliest and latest among 54 stations, by risk level
Risk levelEarliest last frostLatest last frostEarliest first frostLatest first frost
Conservative (10%)May 6MANCHESTER AP, NH USJune 14COLEBROOK 3SW, NH USSeptember 5BERLIN MUNI AP, NH USOctober 42 stations
Typical (30%)April 27MANCHESTER AP, NH USJune 42 stationsSeptember 132 stationsOctober 13MANCHESTER AP, NH US
Aggressive (50%)April 21MANCHESTER AP, NH USMay 31COLEBROOK 3SW, NH USSeptember 18BETHLEHEM 2, NH USOctober 19MANCHESTER AP, NH US

Growing season length

The growing season is the stretch between the last spring frost and the first fall frost at 32°F. NOAA gives it as a length with a chance of being at least that long. Each risk level uses the length with that chance of a shorter season, so Conservative shows the shortest lengths.

Growing season at 32°F: shortest and longest among 54 stations
Risk levelShortestLongest
Conservative (90% chance of at least this long)92 daysCOLEBROOK 3SW, NH US160 daysMANCHESTER AP, NH US
Typical (70% chance of at least this long)103 daysCOLEBROOK 3SW, NH US172 daysMANCHESTER AP, NH US
Aggressive (50% chance of at least this long)112 days2 stations180 daysMANCHESTER AP, NH US
Number of stations by growing season length, Typical (70% chance of at least this long)
Growing seasonStations
100–119 days8
120–139 days17
140–159 days26
160–179 days3

Planting windows across New Hampshire

For each crop, the earliest start and the latest end of its Typical windows among the stations. A window at any one station is shorter and falls inside this span. Transplant dates are for seedlings.

Typical planting windows (30% frost dates): earliest start and latest end among stations
Crop and taskEarliest startLatest endStations
Basil: Transplant outdoorsMay 11June 1854 of 54
Bean: Sow outdoorsApril 27June 454 of 54
Beet: Sow outdoorsMarch 30June 454 of 54
Beet: Sow for fallJune 21August 2454 of 54
Broccoli: Transplant outdoorsMarch 30May 2154 of 54
Broccoli: Transplant for fallJune 11August 2454 of 54
Brussels sprouts: Transplant outdoorsMarch 30May 2154 of 54
Brussels sprouts: Transplant for fallMay 22September 354 of 54
Cabbage: Transplant outdoorsMarch 30May 2154 of 54
Cabbage: Transplant for fallJune 6August 2454 of 54
Cantaloupe: Transplant outdoorsMay 11June 1854 of 54
Cantaloupe: Sow outdoorsMay 11June 1854 of 54
Carrot: Sow outdoorsMarch 30June 454 of 54
Carrot: Sow for fallJune 11August 1454 of 54
Cucumber: Transplant outdoorsMay 4June 1154 of 54
Cucumber: Sow outdoorsApril 27June 454 of 54
Eggplant: Transplant outdoorsMay 11June 1854 of 54
Garlic: Plant for fallSeptember 13October 2754 of 54
Lettuce: Transplant outdoorsMarch 30May 2154 of 54
Lettuce: Sow outdoorsMarch 30May 2154 of 54
Lettuce: Sow for fallJune 11September 354 of 54
Onion: Transplant or plant setsMarch 30May 2154 of 54
Peas: Sow outdoorsMarch 30May 2154 of 54
Peas: Sow for fallJune 19August 2454 of 54
Pepper: Transplant outdoorsMay 11June 1854 of 54
Potato: Plant seed potatoesMarch 30June 454 of 54
Pumpkin: Sow outdoorsMay 11June 1854 of 54
Radish: Sow outdoorsMarch 30May 2154 of 54
Radish: Sow for fallJuly 26September 2354 of 54
Spinach: Transplant outdoorsMarch 30May 2154 of 54
Spinach: Sow outdoorsMarch 30May 2154 of 54
Spinach: Sow for fallJuly 1September 654 of 54
Summer squash: Transplant outdoorsMay 4June 1154 of 54
Summer squash: Sow outdoorsApril 27June 454 of 54
Sweet corn: Sow outdoorsApril 27June 454 of 54
Sweet potato: Plant slipsMay 4June 1854 of 54
Tomato: Transplant outdoorsMay 11June 1854 of 54
Turnip: Sow outdoorsMarch 30May 2154 of 54
Turnip: Sow for fallJuly 1September 354 of 54
Watermelon: Transplant outdoorsMay 11June 1854 of 54
Watermelon: Sow outdoorsMay 11June 1854 of 54

Weather stations in New Hampshire

Every station in New Hampshire with NOAA frost-date normals, with its Typical 32°F frost dates and growing season. 1 of them have no 32°F frost dates.

Data sources

NOAA U.S. Climate Normals, frost dates, 1991–2020 normals, version 1.0.1
Files: us-climate-normals_1991-2020_v1.0.1_annualseasonal_multivariate_by-station_c20230404.tar.gz, inventory_30yr.txt from NOAA NCEI. Retrieved October 10, 2026.