USDA Hardiness Zone 4b
Frost Dates for 03582 — Groveton, New Hampshire
NOAA 1991–2020 normals from N Stratford, NH (950 ft), 7 miles northwest.
Updated
In Groveton, the last spring frost (32°F) is around May 19 in half of years and has passed by June 2 in nine years out of ten. The first fall frost comes around September 29, as early as September 15 one year in ten, leaving a typical freeze-free season of 131 days (NOAA, N Stratford, NH).
- Last spring frost
- May 19
- First fall frost
- September 29
- Growing season
- 131 days
- Hardiness zone
- 4b
50% probability
50% probability
freeze-free, 50%
-25 to -20°F (-31.7 to -28.9°C) coldest night
- First snow
- November 10
- Last snow
- April 16
- Winters with snow
- 100%
- Snow per year
- 79.1"
median, 1991–2020
median, 1991–2020
23 of 23 observed
NOAA normal
Frost risk by date in Groveton
Half of springs at N Stratford, NH see their last 32°F night by May 19; only one in ten is past it by May 2, and one in ten still has one after June 2. Planting tender crops after May 24 leaves a 30% risk of a frost on them, after May 28 20%, and after June 2 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 25% of the 51 New Hampshire stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 29 in half of years, as early as September 15 one year in ten, and holds off past October 10 one year in ten. A hard freeze of 28°F follows 8 days later, around October 7; in spring the one-in-ten date for 28°F is May 19, 14 days before the 32°F one. The freeze-free season lasts 131 days in a typical year, shorter than at 88% of the 51 New Hampshire stations; it reaches 151 days one year in ten and falls short of 112 one year in ten. On average 186 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 June 1, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 13 and April 5.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 18 | May 23 | May 26 | May 29 | Jun 1 | Jun 3 | Jun 6 | Jun 10 | Jun 15 |
| 32°F | May 2 | May 8 | May 12 | May 16 | May 19 | May 22 | May 24 | May 28 | Jun 2 |
| 28°F | Apr 22 | Apr 27 | Apr 29 | May 1 | May 4 | May 6 | May 10 | May 14 | May 19 |
| 24°F | Apr 10 | Apr 15 | Apr 18 | Apr 21 | Apr 23 | Apr 26 | Apr 28 | May 1 | May 5 |
| 20°F | Apr 2 | Apr 5 | Apr 7 | Apr 9 | Apr 11 | Apr 14 | Apr 17 | Apr 21 | Apr 24 |
| 16°F | Mar 26 | Mar 30 | Apr 1 | Apr 3 | Apr 5 | Apr 6 | Apr 8 | Apr 12 | Apr 17 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 4 | Sep 7 | Sep 11 | Sep 14 | Sep 17 | Sep 19 | Sep 22 | Sep 25 | Sep 29 |
| 32°F | Sep 15 | Sep 19 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 2 | Oct 6 | Oct 10 |
| 28°F | Sep 26 | Oct 1 | Oct 2 | Oct 5 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 24 |
| 24°F | Oct 6 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 | Nov 5 |
| 20°F | Oct 17 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 |
| 16°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 22 | Nov 26 |
Freeze probabilities 1991–2020 at N Stratford, 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 03582 →Compare Groveton with another place →
Weather by month in Groveton
July is the warmest month at N Stratford, NH, averaging 79°F by day and 55°F at night; January is the coldest at 25°F and 2°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 13% of years.
Warmth for growing adds up to 1,851 growing degree days a year (base 50°F), fewer than at 78% of the 51 New Hampshire stations. 30% of them (553) have built up by the end of June, and July adds the most, 525. Precipitation totals 40.5 inches a year, most in July (4.5") and least in February (2.2"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 25 | 2 | 2.6 | 100% | 30 | 0 |
| Feb | 28 | 2 | 2.2 | 100% | 28 | 0 |
| Mar | 37 | 14 | 2.4 | 100% | 29 | 2 |
| Apr | 52 | 29 | 3.0 | 100% | 20 | 23 |
| May | 66 | 40 | 3.7 | 91% | 7 | 155 |
| Jun | 74 | 50 | 4.4 | 13% | <1 | 372 |
| Jul | 79 | 55 | 4.5 | 0% | 0 | 525 |
| Aug | 77 | 53 | 4.0 | 0% | 0 | 470 |
| Sep | 70 | 45 | 3.6 | 57% | 3 | 248 |
| Oct | 56 | 34 | 4.2 | 100% | 15 | 50 |
| Nov | 42 | 24 | 2.9 | 100% | 25 | 6 |
| Dec | 31 | 12 | 3.0 | 100% | 30 | 0 |
Monthly normals 1991–2020 at N Stratford, NH (950 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, Lancaster, NH, 9 miles southwest of Groveton, has a last frost 1 day earlier (May 18), a first frost 1 day later (September 30), a season 1 day longer.
When it snows in Groveton, New Hampshire
The first measurable snow (0.1 inch or more) in Groveton usually arrives around November 10, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at N Stratford, NH, 7.1 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 33 days after the last snow.
Planting calendar for 03582
| When | What to do |
|---|---|
| March 10 – March 24 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 24 – April 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 21 – May 5 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 19 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 15 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 29 onward | Plant 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 03582 is 7 miles from N Stratford, NH, which stands at 950 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03582 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°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.