Frost Dates for 20106 — Amissville, Virginia

Half of springs at Boston 4 SE, VA see their last 32°F night by April 21; only one in ten is past it by April 5, and one in ten still has one after May 10. Planting tender crops after April 28 leaves a 30% risk of a frost on them, after May 3 20%, and after May 10 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 70% of the 128 Virginia stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as October 8 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 10 days later, around November 1; in spring the one-in-ten date for 28°F is April 23, 17 days before the 32°F one. The freeze-free season lasts 184 days in a typical year, shorter than at 70% of the 128 Virginia stations; it reaches 205 days one year in ten and falls short of 162 one year in ten. On average 121 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 12 days longer, to about May 3, and return around October 13. Severe cold of 16°F or below comes every winter, usually between December 9 and March 1.

July is the warmest month at Boston 4 SE, VA, averaging 86°F by day and 64°F at night; January is the coldest at 44°F and 23°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 25% of years.

Warmth for growing adds up to 3,472 growing degree days a year (base 50°F), fewer than at 68% of the 128 Virginia stations. 36% of them (1,233) have built up by the end of June, and July adds the most, 770.

The nearest other station, Warrenton 3 SE, VA, 12 miles east of Amissville, has a last frost 12 days earlier (April 9), a first frost 10 days later (November 1), a season 21 days longer.

The first measurable snow (0.1 inch or more) in Amissville usually arrives around December 11, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Rixeyville 2.5 N, VA, 4.7 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 46 days after the last snow.

ZIP 20106 is 11 miles from Boston 4 SE, VA, which stands at 590 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 22701 (Culpeper). The 2023 USDA Plant Hardiness Zone Map lists ZIP 20106 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.