Frost Dates for 08536 — Plainsboro, New Jersey

Half of springs at Hightstown 2 W, 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 12. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 6 20%, and after May 12 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 64% of the 56 New Jersey stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 4 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 12 days later, around October 28; in spring the one-in-ten date for 28°F is April 26, 16 days before the 32°F one. The freeze-free season lasts 173 days in a typical year, shorter than at 89% of the 56 New Jersey stations; it reaches 194 days one year in ten and falls short of 153 one year in ten. On average 114 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 6. Severe cold of 16°F or below comes every winter, usually between December 7 and March 5.

July is the warmest month at Hightstown 2 W, NJ, averaging 87°F by day and 63°F at night; January is the coldest at 41°F and 21°F. A freezing night is all but certain in every month from October 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 34% of years.

Warmth for growing adds up to 3,272 growing degree days a year (base 50°F), fewer than at 70% of the 56 New Jersey stations. 33% of them (1,079) have built up by the end of June, and July adds the most, 770. Precipitation totals 47.6 inches a year, most in July (4.8") and least in February (2.6"); May to September bring 46% of it.

The nearest other station, Trenton State College, NJ, 12 miles west of Plainsboro, has a last frost 8 days earlier (April 17), a first frost 12 days later (October 28), a season 19 days longer.

The first measurable snow (0.1 inch or more) in Plainsboro usually arrives around December 11, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Hightstown 2 W, NJ, 4.8 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 35 days after the last snow.

ZIP 08536 is 5 miles from Hightstown 2 W, NJ, which stands at 100 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 18 other ZIP codes share the station; its figures are presented in full for 08831 (Monroe Township). The 2023 USDA Plant Hardiness Zone Map lists ZIP 08536 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.