Frost Dates for 08889 — Whitehouse Station, New Jersey

Half of springs at Somerville Somerset Airport, NJ see their last 32°F night by April 26; only one in ten is past it by April 11, and one in ten still has one after May 13. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 7 20%, and after May 13 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 18 in half of years, as early as October 5 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 12 days later, around October 30; in spring the one-in-ten date for 28°F is April 28, 15 days before the 32°F one. The freeze-free season lasts 176 days in a typical year, shorter than at 82% of the 56 New Jersey stations; it reaches 198 days one year in ten and falls short of 153 one year in ten. On average 124 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 11 days longer, to about May 7, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 8 and March 5.

July is the warmest month at Somerville Somerset Airport, NJ, averaging 86°F by day and 63°F at night; January is the coldest at 39°F and 21°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 35% of years.

Warmth for growing adds up to 3,215 growing degree days a year (base 50°F), fewer than at 75% of the 56 New Jersey stations. 33% of them (1,057) have built up by the end of June, and July adds the most, 762. Precipitation totals 45.5 inches a year, most in August (5.2") and least in February (2.2"); May to September bring 47% of it.

The nearest other station, Somerville 4 NW, NJ, 6 miles east of Whitehouse Station, has a last frost 4 days later (April 30), a first frost 2 days later (October 20), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Whitehouse Station usually arrives around December 11, and the last of the season around March 24. Those are the middle dates across the winters of 1991–2020 at Somerville 4 NW, NJ, 6 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 33 days after the last snow.

ZIP 08889 is 5 miles from Somerville Somerset Airport, NJ, which stands at 105 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 07853 (Long Valley). The 2023 USDA Plant Hardiness Zone Map lists ZIP 08889 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.