Frost Dates for 22310 — Alexandria, Virginia

Half of springs at Washington Reagan Airport, VA see their last 32°F night by March 24; only one in ten is past it by March 7, and one in ten still has one after April 6. Planting tender crops after March 30 leaves a 30% risk of a frost on them, after April 2 20%, and after April 6 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 91% of the 128 Virginia stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 18 in half of years, as early as November 5 one year in ten, and holds off past December 6 one year in ten. A hard freeze of 28°F follows 15 days later, around December 3; in spring the one-in-ten date for 28°F is March 26, 11 days before the 32°F one. The freeze-free season lasts 241 days in a typical year, longer than at 98% of the 128 Virginia stations; it reaches 265 days one year in ten and falls short of 220 one year in ten. On average 60 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 10 days longer, to about April 3, and return around November 6. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 78%.

July is the warmest month at Washington Reagan Airport, VA, averaging 90°F by day and 72°F at night; January is the coldest at 45°F and 30°F. A freezing night is all but certain in every month from December to March (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 25% of years.

Warmth for growing adds up to 4,709 growing degree days a year (base 50°F), more than at 95% of the 128 Virginia stations. 36% of them (1,701) have built up by the end of June, and July adds the most, 961. Precipitation totals 41.8 inches a year, most in July (4.3") and least in February (2.6"); May to September bring 47% of it.

The nearest other station, Oxon Hill, MD, 7 miles east of Alexandria and 180 feet higher, has a last frost 10 days later (April 3), a first frost 10 days earlier (November 8), a season 24 days shorter.

The first measurable snow (0.1 inch or more) in Alexandria usually arrives around December 19, and the last of the season around March 4. Those are the middle dates across the winters of 1991–2020 at Washington Reagan Airport, VA, 6.6 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 20 days after the last snow.

ZIP 22310 is 7 miles from Washington Reagan Airport, VA, which stands at 10 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 17 other ZIP codes share the station; its figures are presented in full for 22204 (Arlington). The 2023 USDA Plant Hardiness Zone Map lists ZIP 22310 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.