Frost Dates for 62626 — Carlinville, Illinois

Half of springs at Carlinville, IL see their last 32°F night by April 14; only one in ten is past it by March 31, and one in ten still has one after April 30. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 24 20%, and after April 30 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 22% of the 158 Illinois stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 21 in half of years, as early as October 5 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around November 1; in spring the one-in-ten date for 28°F is April 17, 13 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, longer than at 58% of the 158 Illinois stations; it reaches 209 days one year in ten and falls short of 167 one year in ten. On average 110 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 11 days longer, to about April 25, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 3 and March 4.

July is the warmest month at Carlinville, IL, averaging 86°F by day and 66°F at night; January is the coldest at 36°F and 19°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 85% of years.

Warmth for growing adds up to 3,725 growing degree days a year (base 50°F), more than at 69% of the 158 Illinois stations. 37% of them (1,371) have built up by the end of June, and July adds the most, 809. Precipitation totals 39.9 inches a year, most in April (4.7") and least in February (2.1"); May to September bring 47% of it.

The nearest other station, Virden, IL, 17 miles north of Carlinville, has a last frost 7 days earlier (April 7), a first frost 8 days later (October 29), a season 17 days longer.

The first measurable snow (0.1 inch or more) in Carlinville usually arrives around December 11, and the last of the season around March 11. Those are the middle dates across the winters of 1991–2020 at Carlinville, IL, 0.6 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 34 days after the last snow.

ZIP 62626 is under a mile from Carlinville, IL, which stands at 621 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 62626 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.