Frost Dates for 61615 — Peoria, Illinois

Half of springs at Peoria Gtr Peoria Airport, IL see their last 32°F night by April 16; only one in ten is past it by April 2, and one in ten still has one after May 4. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 28 20%, and after May 4 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 92% of the 158 Illinois stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 23 in half of years, as early as October 9 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 10 days later, around November 2; in spring the one-in-ten date for 28°F is April 21, 13 days before the 32°F one. The freeze-free season lasts 189 days in a typical year, longer than at 62% of the 158 Illinois stations; it reaches 209 days one year in ten and falls short of 167 one year in ten. On average 118 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 27, 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 Peoria Gtr Peoria Airport, IL, averaging 86°F by day and 66°F at night; January is the coldest at 34°F and 18°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 15% of years.

Warmth for growing adds up to 3,670 growing degree days a year (base 50°F), more than at 65% of the 158 Illinois stations. 36% of them (1,321) have built up by the end of June, and July adds the most, 815. Precipitation totals 37.6 inches a year, most in May (4.7") and least in February (2.0"); May to September bring 50% of it.

The nearest other station, Princeville, IL, 13 miles northwest of Peoria, has a last frost 6 days later (April 22), a first frost 9 days earlier (October 14), a season 15 days shorter.

The first measurable snow (0.1 inch or more) in Peoria usually arrives around December 1, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Peoria Gtr Peoria Airport, IL, 7 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 27 days after the last snow.

ZIP 61615 is 7 miles from Peoria Gtr Peoria Airport, IL, which stands at 650 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 16 other ZIP codes share the station; its figures are presented in full for 61554 (Pekin). The 2023 USDA Plant Hardiness Zone Map lists ZIP 61615 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.