Frost Dates for 60950 — Manteno, Illinois

Half of springs at Kankakee Metro Wastewater, IL see their last 32°F night by April 19; only one in ten is past it by April 5, and one in ten still has one after May 3. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 28 20%, and after May 3 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 82% of the 158 Illinois stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 24 in half of years, as early as October 12 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 11 days later, around November 4; in spring the one-in-ten date for 28°F is April 22, 11 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 207 days one year in ten and falls short of 167 one year in ten. On average 129 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 30, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 2 and March 7.

July is the warmest month at Kankakee Metro Wastewater, IL, averaging 85°F by day and 65°F at night; January is the coldest at 33°F and 16°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 14% of years.

Warmth for growing adds up to 3,373 growing degree days a year (base 50°F), fewer than at 58% of the 158 Illinois stations. 35% of them (1,169) have built up by the end of June, and July adds the most, 769. Precipitation totals 41.9 inches a year, most in May (5.2") and least in February (1.9"); May to September bring 54% of it.

The nearest other station, Park Forest, IL, 19 miles northeast of Manteno, has a last frost 4 days later (April 23), a first frost 4 days earlier (October 20), a season 9 days shorter.

The first measurable snow (0.1 inch or more) in Manteno usually arrives around December 3, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Kankakee Metro Wastewater, IL, 8.2 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 29 days after the last snow.

ZIP 60950 is 8 miles from Kankakee Metro Wastewater, IL, which stands at 600 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 60901 (Kankakee). The 2023 USDA Plant Hardiness Zone Map lists ZIP 60950 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.