USDA Hardiness Zone 5a
Frost Dates for 03585 — Lisbon, New Hampshire
NOAA 1991–2020 normals from Bethlehem 2, NH (1,180 ft), 12 miles northeast.
Updated
In Lisbon, the last spring frost (32°F) is around May 24 in half of years and has passed by June 8 in nine years out of ten. The first fall frost comes around September 18, as early as September 6 one year in ten, leaving a typical freeze-free season of 116 days (NOAA, Bethlehem 2, NH).
- Last spring frost
- May 24
- First fall frost
- September 18
- Growing season
- 116 days
- Hardiness zone
- 5a
50% probability
50% probability
freeze-free, 50%
-20 to -15°F (-28.9 to -26.1°C) coldest night
- First snow
- October 31
- Last snow
- April 17
- Winters with snow
- 100%
- Snow per year
- 100.9"
median, 1991–2020
median, 1991–2020
19 of 19 observed
NOAA normal
Frost risk by date in Lisbon
Half of springs at Bethlehem 2, NH see their last 32°F night by May 24; only one in ten is past it by May 6, and one in ten still has one after June 8. Planting tender crops after May 31 leaves a 30% risk of a frost on them, after June 3 20%, and after June 8 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 76% of the 51 New Hampshire stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 18 in half of years, as early as September 6 one year in ten, and holds off past October 1 one year in ten. A hard freeze of 28°F follows 12 days later, around September 30; in spring the one-in-ten date for 28°F is May 27, 12 days before the 32°F one. The freeze-free season lasts 116 days in a typical year, shorter than at 96% of the 51 New Hampshire stations; it reaches 137 days one year in ten and falls short of 97 one year in ten. On average 191 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 12 days longer, to about June 5, and return around September 7. Severe cold of 16°F or below comes every winter, usually between November 11 and April 4.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 22 | May 27 | May 31 | Jun 3 | Jun 5 | Jun 8 | Jun 11 | Jun 15 | Jun 24 |
| 32°F | May 6 | May 12 | May 17 | May 21 | May 24 | May 28 | May 31 | Jun 3 | Jun 8 |
| 28°F | Apr 24 | Apr 28 | May 1 | May 4 | May 7 | May 11 | May 16 | May 21 | May 27 |
| 24°F | Apr 12 | Apr 16 | Apr 20 | Apr 23 | Apr 26 | Apr 28 | May 1 | May 5 | May 10 |
| 20°F | Apr 3 | Apr 5 | Apr 8 | Apr 10 | Apr 13 | Apr 15 | Apr 18 | Apr 21 | Apr 24 |
| 16°F | Mar 26 | Mar 31 | Apr 1 | Apr 3 | Apr 4 | Apr 6 | Apr 9 | Apr 12 | Apr 17 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 25 | Aug 31 | Sep 2 | Sep 5 | Sep 7 | Sep 10 | Sep 13 | Sep 16 | Sep 20 |
| 32°F | Sep 6 | Sep 10 | Sep 13 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Sep 27 | Oct 1 |
| 28°F | Sep 15 | Sep 19 | Sep 23 | Sep 26 | Sep 30 | Oct 1 | Oct 5 | Oct 8 | Oct 14 |
| 24°F | Sep 27 | Oct 1 | Oct 5 | Oct 9 | Oct 13 | Oct 17 | Oct 21 | Oct 25 | Nov 1 |
| 20°F | Oct 8 | Oct 15 | Oct 19 | Oct 25 | Oct 28 | Nov 1 | Nov 4 | Nov 9 | Nov 14 |
| 16°F | Oct 22 | Oct 30 | Nov 2 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 26 |
Freeze probabilities 1991–2020 at Bethlehem 2, 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 03585 →Compare Lisbon with another place →
Weather by month in Lisbon
July is the warmest month at Bethlehem 2, NH, averaging 80°F by day and 53°F at night; January is the coldest at 28°F and 3°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 28% of years.
Warmth for growing adds up to 1,780 growing degree days a year (base 50°F), fewer than at 92% of the 51 New Hampshire stations. 30% of them (539) have built up by the end of June, and July adds the most, 510. Precipitation totals 41.0 inches a year, most in July (4.6") and least in February (2.0"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 28 | 3 | 2.6 | 100% | 31 | 1 |
| Feb | 30 | 4 | 2.0 | 100% | 28 | 0 |
| Mar | 40 | 14 | 2.6 | 100% | 29 | 2 |
| Apr | 53 | 27 | 3.2 | 100% | 21 | 23 |
| May | 67 | 39 | 3.7 | 95% | 7 | 156 |
| Jun | 76 | 48 | 4.2 | 28% | <1 | 358 |
| Jul | 80 | 53 | 4.6 | 0% | 0 | 510 |
| Aug | 79 | 50 | 4.2 | 0% | 0 | 450 |
| Sep | 72 | 42 | 3.6 | 86% | 5 | 229 |
| Oct | 58 | 32 | 4.0 | 100% | 16 | 46 |
| Nov | 45 | 24 | 3.0 | 100% | 25 | 6 |
| Dec | 33 | 12 | 3.3 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Bethlehem 2, NH (1,180 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, Benton 5 SW, NH, 14 miles south of Lisbon, has a last frost 9 days earlier (May 15), a first frost 10 days later (September 28), a season 17 days longer.
When it snows in Lisbon, New Hampshire
The first measurable snow (0.1 inch or more) in Lisbon usually arrives around October 31, and the last of the season around April 17. Those are the middle dates across the winters of 1991–2020 at Bethlehem 2, NH, 12.1 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 37 days after the last snow.
Planting calendar for 03585
| When | What to do |
|---|---|
| March 15 – March 29 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 29 – April 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 26 – May 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 26 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 4 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 18 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 03585 is 12 miles from Bethlehem 2, NH, which stands at 1,180 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 03561 (Littleton). The 2023 USDA Plant Hardiness Zone Map lists ZIP 03585 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°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.