Frost Dates for 35043 — Chelsea, Alabama

Half of springs at Helena, AL see their last 32°F night by March 19; only one in ten is past it by February 26, and one in ten still has one after April 9. Planting tender crops after March 29 leaves a 30% risk of a frost on them, after April 2 20%, and after April 9 10%. The 21 days between the even-odds date and the one-in-ten date is wider than at 88% of the 115 Alabama stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by November 8 in half of years, as early as October 26 one year in ten, and holds off past November 29 one year in ten. A hard freeze of 28°F follows 14 days later, around November 22; in spring the one-in-ten date for 28°F is March 25, 15 days before the 32°F one. The freeze-free season lasts 236 days in a typical year, longer than at 58% of the 115 Alabama stations; it reaches 261 days one year in ten and falls short of 210 one year in ten. On average 51 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 15 days longer, to about April 3, and return around October 30. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 61%.

July is the warmest month at Helena, AL, averaging 92°F by day and 71°F at night; January is the coldest at 55°F and 35°F. A freezing night is all but certain in every month from December to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 82% of years and April still brings one in 24% of years.

Warmth for growing adds up to 5,766 growing degree days a year (base 50°F), more than at 62% of the 115 Alabama stations. 41% of them (2,357) have built up by the end of June, and July adds the most, 983. Precipitation totals 55.7 inches a year, most in February (5.6") and least in October (3.6"); May to September bring 39% of it.

The nearest other station, Alabaster Shelby Co Airport, AL, 12 miles southwest of Chelsea, has a last frost 7 days earlier (March 12), a first frost 8 days later (November 16), a season 12 days longer.

Measurable snow is rare here: only 1 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Leeds, AL, 15 miles away, so there is no typical first-snow date to plan around.

ZIP 35043 is 10 miles from Helena, AL, which stands at 480 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 35226 (Hoover). The 2023 USDA Plant Hardiness Zone Map lists ZIP 35043 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.