Frost Dates for 22435 — Callao, Virginia

Half of springs at Warsaw 2 NW, VA see their last 32°F night by April 8; only one in ten is past it by March 26, and one in ten still has one after April 23. Planting tender crops after April 14 leaves a 30% risk of a frost on them, after April 18 20%, and after April 23 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 70% of the 128 Virginia stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 30 in half of years, as early as October 15 one year in ten, and holds off past November 12 one year in ten. A hard freeze of 28°F follows 11 days later, around November 10; in spring the one-in-ten date for 28°F is April 10, 13 days before the 32°F one. The freeze-free season lasts 204 days in a typical year, longer than at 64% of the 128 Virginia stations; it reaches 223 days one year in ten and falls short of 183 one year in ten. On average 77 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 14 days longer, to about April 22, and return around October 20. Severe cold of 16°F or below comes in 98% of winters, usually between December 30 and February 18.

July is the warmest month at Warsaw 2 NW, VA, averaging 88°F by day and 68°F at night; January is the coldest at 47°F and 29°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 77% of years.

Warmth for growing adds up to 4,351 growing degree days a year (base 50°F), more than at 76% of the 128 Virginia stations. 37% of them (1,617) have built up by the end of June, and July adds the most, 876. Precipitation totals 45.3 inches a year, most in August (5.0") and least in February (2.6"); May to September bring 49% of it.

The nearest other station, St Inigoes Webster Nolf, MD, 12 miles northeast of Callao, has a last frost 9 days earlier (March 30), a first frost 15 days later (November 14), a season 25 days longer.

The first measurable snow (0.1 inch or more) in Callao usually arrives around December 25, and the last of the season around February 25. Those are the middle dates across the winters of 1991–2020 at Warsaw 2 NW, VA, 11.6 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 42 days after the last snow.

ZIP 22435 is 12 miles from Warsaw 2 NW, VA, which stands at 140 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 22443 (Colonial Beach). The 2023 USDA Plant Hardiness Zone Map lists ZIP 22435 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.