USDA Hardiness Zone 7a
Frost Dates for 08094 — Williamstown, New Jersey
NOAA 1991–2020 normals from Hammonton 1 NE, NJ (125 ft), 8 miles east.
Updated
In Williamstown, the last spring frost (32°F) is around April 14 in half of years and has passed by April 27 in nine years out of ten. The first fall frost comes around October 27, as early as October 13 one year in ten, leaving a typical freeze-free season of 196 days (NOAA, Hammonton 1 NE, NJ).
- Last spring frost
- April 14
- First fall frost
- October 27
- Growing season
- 196 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
- December 10
- Last snow
- March 13
- Winters with snow
- 94%
- Snow per year
- 19"
median, 1991–2020
median, 1991–2020
16 of 17 observed
NOAA normal
Frost risk by date in Williamstown
Half of springs at Hammonton 1 NE, NJ see their last 32°F night by April 14; only one in ten is past it by April 1, and one in ten still has one after April 27. Planting tender crops after April 19 leaves a 30% risk of a frost on them, after April 22 20%, and after April 27 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 82% of the 56 New Jersey stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 27 in half of years, as early as October 13 one year in ten, and holds off past November 8 one year in ten. A hard freeze of 28°F follows 9 days later, around November 5; in spring the one-in-ten date for 28°F is April 16, 11 days before the 32°F one. The freeze-free season lasts 196 days in a typical year, longer than at 55% of the 56 New Jersey stations; it reaches 214 days one year in ten and falls short of 175 one year in ten. On average 105 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 27, and return around October 16. Severe cold of 16°F or below comes every winter, usually between December 19 and March 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 13 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 6 | May 12 |
| 32°F | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 19 | Apr 22 | Apr 27 |
| 28°F | Mar 21 | Mar 25 | Mar 29 | Mar 31 | Apr 2 | Apr 4 | Apr 7 | Apr 11 | Apr 16 |
| 24°F | Mar 8 | Mar 13 | Mar 17 | Mar 20 | Mar 22 | Mar 25 | Mar 28 | Mar 31 | Apr 3 |
| 20°F | Feb 27 | Mar 3 | Mar 7 | Mar 9 | Mar 13 | Mar 16 | Mar 19 | Mar 22 | Mar 26 |
| 16°F | Feb 11 | Feb 18 | Feb 24 | Feb 28 | Mar 3 | Mar 7 | Mar 10 | Mar 14 | Mar 19 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 31 |
| 32°F | Oct 13 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 8 |
| 28°F | Oct 24 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 19 |
| 24°F | Nov 2 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 3 |
| 20°F | Nov 13 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 10 | Dec 15 | Dec 23 |
| 16°F | Nov 26 | Dec 2 | Dec 7 | Dec 14 | Dec 19 | Dec 24 | Dec 29 | Jan 3 | Jan 12 |
Freeze probabilities 1991–2020 at Hammonton 1 NE, 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 08094 →Compare Williamstown with another place →
Weather by month in Williamstown
July is the warmest month at Hammonton 1 NE, NJ, averaging 87°F by day and 67°F at night; January is the coldest at 42°F and 24°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 3,643 growing degree days a year (base 50°F), more than at 64% of the 56 New Jersey stations. 33% of them (1,211) have built up by the end of June, and July adds the most, 834. Precipitation totals 47.7 inches a year, most in August (4.7") and least in February (2.9"); May to September bring 44% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 42 | 24 | 3.5 | 100% | 25 | 6 |
| Feb | 45 | 25 | 2.9 | 100% | 23 | 7 |
| Mar | 52 | 31 | 4.3 | 100% | 18 | 30 |
| Apr | 64 | 41 | 3.7 | 91% | 4 | 140 |
| May | 73 | 51 | 3.5 | 5% | 0 | 378 |
| Jun | 82 | 61 | 4.1 | 0% | 0 | 650 |
| Jul | 87 | 67 | 4.5 | 0% | 0 | 834 |
| Aug | 85 | 64 | 4.7 | 0% | 0 | 767 |
| Sep | 79 | 57 | 4.1 | 0% | 0 | 539 |
| Oct | 67 | 45 | 4.3 | 68% | 1 | 226 |
| Nov | 56 | 35 | 3.5 | 100% | 12 | 55 |
| Dec | 47 | 29 | 4.6 | 100% | 22 | 12 |
Monthly normals 1991–2020 at Hammonton 1 NE, NJ (125 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, Glassboro 2 NE, NJ, 9 miles northwest of Williamstown, has a last frost 6 days earlier (April 8), a first frost 5 days later (November 1), a season 9 days longer.
When it snows in Williamstown, New Jersey
The first measurable snow (0.1 inch or more) in Williamstown usually arrives around December 10, and the last of the season around March 13. Those are the middle dates across the winters of 1991–2020 at Hammonton 1 NE, NJ, 8.2 miles away: half of years saw snow earlier, half later. Snow fell in 94% of those winters. The last 32°F night of spring typically comes 32 days after the last snow.
Planting calendar for 08094
| When | What to do |
|---|---|
| February 3 – February 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 17 – March 3 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 17 – March 31 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 14 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 4 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 13 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 27 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 08094 is 8 miles from Hammonton 1 NE, NJ, which stands at 125 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 08094 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.