Frost Dates for 21635 — Galena, Maryland

Half of springs at Chestertown, MD see their last 32°F night by April 3; only one in ten is past it by March 20, and one in ten still has one after April 16. Planting tender crops after April 7 leaves a 30% risk of a frost on them, after April 11 20%, and after April 16 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 50 Maryland stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 5 in half of years, as early as October 24 one year in ten, and holds off past November 20 one year in ten. A hard freeze of 28°F follows 12 days later, around November 17; in spring the one-in-ten date for 28°F is April 3, 13 days before the 32°F one. The freeze-free season lasts 217 days in a typical year, longer than at 64% of the 50 Maryland stations; it reaches 237 days one year in ten and falls short of 198 one year in ten. On average 97 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 15, and return around October 26. Severe cold of 16°F or below comes in 95% of winters, usually between January 5 and February 14.

July is the warmest month at Chestertown, MD, averaging 87°F by day and 69°F at night; January is the coldest at 41°F and 27°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 59% of years.

Warmth for growing adds up to 3,938 growing degree days a year (base 50°F), more than at 56% of the 50 Maryland stations. 35% of them (1,372) have built up by the end of June, and July adds the most, 857. Precipitation totals 46.1 inches a year, most in September (4.9") and least in February (2.9"); May to September bring 46% of it.

The nearest other station, Aberdeen Phillips Field, MD, 19 miles northwest of Galena, has a last frost 7 days later (April 10), a first frost 6 days earlier (October 30), a season 16 days shorter.

The first measurable snow (0.1 inch or more) in Galena usually arrives around December 27, and the last of the season around March 2. Those are the middle dates across the winters of 1991–2020 at Chestertown, MD, 14 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 32 days after the last snow.

ZIP 21635 is 14 miles from Chestertown, MD, which stands at 40 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 21620 (Chestertown). The 2023 USDA Plant Hardiness Zone Map lists ZIP 21635 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.