Frost Dates for 62910 — Brookport, Illinois

Half of springs at Brookport Dam 52, IL see their last 32°F night by April 6; only one in ten is past it by March 21, and one in ten still has one after April 23. Planting tender crops after April 12 leaves a 30% risk of a frost on them, after April 17 20%, and after April 23 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 79% of the 158 Illinois stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 27 in half of years, as early as October 15 one year in ten, and holds off past November 9 one year in ten. A hard freeze of 28°F follows 9 days later, around November 5; in spring the one-in-ten date for 28°F is April 11, 12 days before the 32°F one. The freeze-free season lasts 203 days in a typical year, longer than at 92% of the 158 Illinois stations; it reaches 224 days one year in ten and falls short of 182 one year in ten. On average 83 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 13 days longer, to about April 19, and return around October 18. Severe cold of 16°F or below comes every winter, usually between December 11 and February 22.

July is the warmest month at Brookport Dam 52, IL, averaging 89°F by day and 68°F at night; January is the coldest at 43°F and 25°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 70% of years.

Warmth for growing adds up to 4,362 growing degree days a year (base 50°F), more than at 96% of the 158 Illinois stations. 38% of them (1,641) have built up by the end of June, and July adds the most, 880. Precipitation totals 49.2 inches a year, most in April (5.1") and least in August (2.9"); May to September bring 40% of it.

The nearest other station, Smithland L&D, IL, 8 miles east of Brookport, has a last frost 3 days earlier (April 3), a first frost 3 days later (October 30), a season 4 days longer.

The first measurable snow (0.1 inch or more) in Brookport usually arrives around December 23, and the last of the season around February 8. Those are the middle dates across the winters of 1991–2020 at Brookport Dam 52, IL, 4 miles away: half of years saw snow earlier, half later. Snow fell in 73% of those winters. The last 32°F night of spring typically comes 57 days after the last snow.

ZIP 62910 is 4 miles from Brookport Dam 52, IL, which stands at 330 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 42001 (Paducah). The 2023 USDA Plant Hardiness Zone Map lists ZIP 62910 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.