USDA Hardiness Zone 7a
Frost Dates for 08530 — Lambertville, New Jersey
NOAA 1991–2020 normals from Lambertville, NJ (68 ft), 1 miles southwest.
Updated
In Lambertville, the last spring frost (32°F) is around April 16 in half of years and has passed by April 30 in nine years out of ten. The first fall frost comes around October 19, as early as October 4 one year in ten, leaving a typical freeze-free season of 185 days (NOAA, Lambertville, NJ).
- Last spring frost
- April 16
- First fall frost
- October 19
- Growing season
- 185 days
- Hardiness zone
- 7a
50% probability
50% probability
freeze-free, 50%
0 to 5°F (-17.8 to -15.0°C) coldest night
- First snow
- January 2
- Last snow
- March 8
- Winters with snow
- 75%
- Snow per year
- 13.4"
median, 1991–2020
median, 1991–2020
12 of 16 observed
NOAA normal
Frost risk by date in Lambertville
Half of springs at Lambertville, NJ see their last 32°F night by April 16; only one in ten is past it by April 2, and one in ten still has one after April 30. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 25 20%, and after April 30 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 66% of the 56 New Jersey stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 19 in half of years, as early as October 4 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 13 days later, around November 1; in spring the one-in-ten date for 28°F is April 17, 13 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, shorter than at 70% of the 56 New Jersey stations; it reaches 207 days one year in ten and falls short of 165 one year in ten. On average 136 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 April 29, and return around October 8. Severe cold of 16°F or below comes every winter, usually between December 11 and March 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 29 | May 1 | May 4 | May 9 | May 14 |
| 32°F | Apr 2 | Apr 7 | Apr 10 | Apr 14 | Apr 16 | Apr 18 | Apr 21 | Apr 25 | Apr 30 |
| 28°F | Mar 21 | Mar 26 | Mar 30 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 12 | Apr 17 |
| 24°F | Mar 8 | Mar 14 | Mar 18 | Mar 21 | Mar 24 | Mar 27 | Mar 30 | Apr 2 | Apr 5 |
| 20°F | Feb 26 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 16 | Mar 19 | Mar 23 | Mar 28 |
| 16°F | Feb 5 | Feb 16 | Feb 24 | Feb 28 | Mar 3 | Mar 5 | Mar 9 | Mar 14 | Mar 19 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 19 | Oct 26 |
| 32°F | Oct 4 | Oct 8 | Oct 12 | Oct 16 | Oct 19 | Oct 23 | Oct 27 | Nov 1 | Nov 4 |
| 28°F | Oct 12 | Oct 18 | Oct 23 | Oct 27 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 14 |
| 24°F | Oct 23 | Oct 30 | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 22 | Nov 27 |
| 20°F | Nov 7 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 13 |
| 16°F | Nov 24 | Nov 30 | Dec 3 | Dec 7 | Dec 11 | Dec 16 | Dec 21 | Dec 26 | Jan 2 |
Freeze probabilities 1991–2020 at Lambertville, NJ, 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 08530 →Compare Lambertville with another place →
Weather by month in Lambertville
July is the warmest month at Lambertville, NJ, averaging 88°F by day and 64°F at night; January is the coldest at 42°F and 19°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 3,377 growing degree days a year (base 50°F), fewer than at 63% of the 56 New Jersey stations. 34% of them (1,132) have built up by the end of June, and July adds the most, 801. Precipitation totals 50.4 inches a year, most in July (5.1") and least in February (2.9"); May to September bring 46% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 42 | 19 | 3.7 | 100% | 27 | 2 |
| Feb | 44 | 22 | 2.9 | 100% | 24 | 1 |
| Mar | 52 | 29 | 4.3 | 100% | 21 | 19 |
| Apr | 64 | 39 | 3.8 | 91% | 10 | 125 |
| May | 74 | 49 | 4.3 | 8% | <1 | 370 |
| Jun | 83 | 58 | 4.8 | 0% | 0 | 616 |
| Jul | 88 | 64 | 5.1 | 0% | 0 | 801 |
| Aug | 87 | 61 | 4.7 | 0% | 0 | 732 |
| Sep | 80 | 54 | 4.4 | 4% | <1 | 503 |
| Oct | 68 | 40 | 4.3 | 78% | 9 | 171 |
| Nov | 56 | 32 | 3.5 | 100% | 18 | 33 |
| Dec | 46 | 25 | 4.6 | 100% | 26 | 5 |
Monthly normals 1991–2020 at Lambertville, NJ (68 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, Trenton Mercer Co Airport, NJ, 9 miles southeast of Lambertville, has a last frost 6 days earlier (April 10), a first frost 13 days later (November 1), a season 17 days longer.
When it snows in Lambertville, New Jersey
The first measurable snow (0.1 inch or more) in Lambertville usually arrives around January 2, and the last of the season around March 8. Those are the middle dates across the winters of 1991–2020 at Lambertville, NJ, 1.3 miles away: half of years saw snow earlier, half later. Snow fell in 75% of those winters. The last 32°F night of spring typically comes 39 days after the last snow.
Planting calendar for 08530
| When | What to do |
|---|---|
| February 5 – February 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 19 – March 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 19 – April 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 27 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 5 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 19 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 08530 is 1 mile from Lambertville, NJ, which stands at 68 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 18938 (New Hope). The 2023 USDA Plant Hardiness Zone Map lists ZIP 08530 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across New Jersey →
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.