Frost Dates for 20198 — The Plains, Virginia

Half of springs at Mt Wx, VA see their last 32°F night by April 17; only one in ten is past it by April 3, and one in ten still has one after May 6. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 30 20%, and after May 6 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 November 1 in half of years, as early as October 17 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 10 days later, around November 11; in spring the one-in-ten date for 28°F is April 23, 13 days before the 32°F one. The freeze-free season lasts 198 days in a typical year, longer than at 51% of the 128 Virginia stations; it reaches 217 days one year in ten and falls short of 173 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 12 days longer, to about April 29, and return around October 21. Severe cold of 16°F or below comes every winter, usually between December 17 and March 9.

July is the warmest month at Mt Wx, VA, averaging 82°F by day and 65°F at night; January is the coldest at 40°F and 22°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 18% of years.

Warmth for growing adds up to 3,269 growing degree days a year (base 50°F), fewer than at 78% of the 128 Virginia stations. 34% of them (1,119) have built up by the end of June, and July adds the most, 732. Precipitation totals 46.5 inches a year, most in September (5.3") and least in February (3.0"); May to September bring 49% of it.

The nearest other station, Mt Wx 3, VA, 14 miles northwest of The Plains, has the same 50% last-frost date, a first frost 3 days earlier (October 29), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in The Plains usually arrives around December 24, and the last of the season around February 21. Those are the middle dates across the winters of 1991–2020 at The Plains 2 NNE, VA, 0.4 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 55 days after the last snow.

ZIP 20198 is 14 miles from Mt Wx, VA, which stands at 1,659 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 20135 (Bluemont). The 2023 USDA Plant Hardiness Zone Map lists ZIP 20198 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.