USDA Hardiness Zone 6a
Frost Dates for 03063 — Nashua, New Hampshire
NOAA 1991–2020 normals from Nashua 2 NNW, NH (135 ft), 2 miles northeast.
Updated
In Nashua, 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
- First fall frost
- October 12
- Growing season
- 165 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- December 3
- Last snow
- March 25
- Winters with snow
- 100%
- Snow per year
- 52.9"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Nashua
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.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 30 | May 3 | May 5 | May 8 | May 10 | May 13 | May 16 | May 19 | May 23 |
| 32°F | Apr 18 | Apr 22 | Apr 24 | Apr 27 | Apr 30 | May 1 | May 4 | May 6 | May 11 |
| 28°F | Apr 3 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 19 | Apr 21 | Apr 24 | Apr 29 |
| 24°F | Mar 23 | Mar 29 | Mar 31 | Apr 2 | Apr 4 | Apr 5 | Apr 8 | Apr 11 | Apr 16 |
| 20°F | Mar 11 | Mar 16 | Mar 19 | Mar 23 | Mar 26 | Mar 29 | Mar 31 | Apr 2 | Apr 5 |
| 16°F | Mar 3 | Mar 8 | Mar 11 | Mar 14 | Mar 16 | Mar 19 | Mar 23 | Mar 26 | Mar 30 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 25 | Sep 28 | Sep 30 | Oct 2 | Oct 4 | Oct 6 | Oct 10 | Oct 15 |
| 32°F | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 22 | Oct 28 |
| 28°F | Oct 8 | Oct 13 | Oct 18 | Oct 22 | Oct 24 | Oct 28 | Nov 1 | Nov 3 | Nov 7 |
| 24°F | Oct 22 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 15 | Nov 20 |
| 20°F | Nov 3 | Nov 9 | Nov 12 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 3 |
| 16°F | Nov 14 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 2 | Dec 5 | Dec 10 | Dec 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 03063 →Compare Nashua with another place →
Weather by month in Nashua
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.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 34 | 14 | 3.4 | 100% | 30 | 0 |
| Feb | 37 | 15 | 3.2 | 100% | 27 | 0 |
| Mar | 45 | 23 | 4.3 | 100% | 26 | 7 |
| Apr | 59 | 34 | 4.2 | 100% | 14 | 60 |
| May | 70 | 46 | 3.9 | 44% | 1 | 262 |
| Jun | 78 | 56 | 4.3 | 0% | 0 | 513 |
| Jul | 84 | 61 | 3.7 | 0% | 0 | 704 |
| Aug | 83 | 59 | 3.9 | 0% | 0 | 649 |
| Sep | 75 | 51 | 4.1 | 11% | <1 | 400 |
| Oct | 63 | 39 | 4.8 | 92% | 8 | 110 |
| Nov | 51 | 30 | 3.9 | 100% | 21 | 16 |
| Dec | 40 | 21 | 4.5 | 100% | 28 | 1 |
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, Nashua Cwsu, NH, 3 miles southeast of Nashua, has a last frost 1 day earlier (April 29), a first frost 4 days earlier (October 8), a season 3 days shorter.
When it snows in Nashua, New Hampshire
The first measurable snow (0.1 inch or more) in Nashua 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, 2.4 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 03063
| When | What to do |
|---|---|
| February 19 – March 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 5 – March 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 2 – April 16 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 30 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 28 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 12 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 03063 is 2 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 03063 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.