USDA Hardiness Zone 6b
Frost Dates for 07438 — Oak Ridge, New Jersey
NOAA 1991–2020 normals from Charlotteburg Rsvr, NJ (778 ft), 4 miles east.
Updated
In Oak Ridge, the last spring frost (32°F) is around April 25 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 17, as early as October 2 one year in ten, leaving a typical freeze-free season of 174 days (NOAA, Charlotteburg Rsvr, NJ).
- Last spring frost
- April 25
- First fall frost
- October 17
- Growing season
- 174 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- December 13
- Last snow
- March 20
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
24 of 24 observed
NOAA normal
Frost risk by date in Oak Ridge
Half of springs at Charlotteburg Rsvr, NJ see their last 32°F night by April 25; only one in ten is past it by April 12, and one in ten still has one after May 11. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 5 20%, and after May 11 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 38% of the 56 New Jersey stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 17 in half of years, as early as October 2 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 14 days later, around October 31; in spring the one-in-ten date for 28°F is April 26, 15 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, shorter than at 88% of the 56 New Jersey stations; it reaches 197 days one year in ten and falls short of 152 one year in ten. On average 138 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 May 8, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 7 and March 10.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 23 | Apr 28 | May 1 | May 4 | May 8 | May 11 | May 15 | May 19 | May 24 |
| 32°F | Apr 12 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 28 | May 1 | May 5 | May 11 |
| 28°F | Mar 30 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 26 |
| 24°F | Mar 15 | Mar 21 | Mar 25 | Mar 29 | Mar 31 | Apr 2 | Apr 3 | Apr 7 | Apr 11 |
| 20°F | Mar 2 | Mar 8 | Mar 13 | Mar 16 | Mar 19 | Mar 22 | Mar 26 | Mar 30 | Apr 1 |
| 16°F | Feb 22 | Feb 28 | Mar 3 | Mar 7 | Mar 10 | Mar 13 | Mar 16 | Mar 20 | Mar 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 30 | Oct 1 | Oct 4 | Oct 7 | Oct 9 | Oct 12 | Oct 16 | Oct 21 |
| 32°F | Oct 2 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 21 | Oct 25 | Oct 29 | Nov 3 |
| 28°F | Oct 14 | Oct 19 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 6 | Nov 9 | Nov 15 |
| 24°F | Oct 28 | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 18 | Nov 22 | Nov 28 |
| 20°F | Nov 10 | Nov 15 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 1 | Dec 5 | Dec 13 |
| 16°F | Nov 19 | Nov 27 | Dec 1 | Dec 3 | Dec 7 | Dec 11 | Dec 16 | Dec 21 | Dec 28 |
Freeze probabilities 1991–2020 at Charlotteburg Rsvr, 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 07438 →Compare Oak Ridge with another place →
Weather by month in Oak Ridge
July is the warmest month at Charlotteburg Rsvr, NJ, averaging 83°F by day and 61°F at night; January is the coldest at 36°F and 19°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 32% of years.
Warmth for growing adds up to 2,784 growing degree days a year (base 50°F), fewer than at 96% of the 56 New Jersey stations. 32% of them (892) have built up by the end of June, and July adds the most, 687. Precipitation totals 52.3 inches a year, most in October (5.0") and least in February (3.2"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 36 | 19 | 4.1 | 100% | 28 | 1 |
| Feb | 39 | 19 | 3.2 | 100% | 26 | 1 |
| Mar | 47 | 27 | 4.5 | 100% | 24 | 12 |
| Apr | 59 | 38 | 4.2 | 99% | 9 | 81 |
| May | 70 | 48 | 4.0 | 32% | 1 | 280 |
| Jun | 78 | 57 | 4.9 | 0% | 0 | 518 |
| Jul | 83 | 61 | 4.6 | 0% | 0 | 687 |
| Aug | 81 | 60 | 4.3 | 0% | 0 | 632 |
| Sep | 75 | 52 | 4.9 | 4% | <1 | 410 |
| Oct | 63 | 41 | 5.0 | 82% | 6 | 137 |
| Nov | 51 | 32 | 3.8 | 100% | 18 | 23 |
| Dec | 41 | 25 | 4.8 | 100% | 26 | 3 |
Monthly normals 1991–2020 at Charlotteburg Rsvr, NJ (778 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, Boonton 1 SE, NJ, 11 miles southeast of Oak Ridge and 498 feet lower, has a last frost 8 days earlier (April 17), a first frost 6 days later (October 23), a season 15 days longer.
When it snows in Oak Ridge, New Jersey
The first measurable snow (0.1 inch or more) in Oak Ridge usually arrives around December 13, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Charlotteburg Rsvr, NJ, 4.3 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 07438
| When | What to do |
|---|---|
| February 14 – February 28 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 28 – March 14 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 28 – April 11 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 25 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 25 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 3 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 17 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 07438 is 4 miles from Charlotteburg Rsvr, NJ, which stands at 778 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 07405 (Kinnelon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 07438 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°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.