Frost Dates for 62837 — Fairfield, Illinois

Half of springs at Fairfield Radio Wfiw, IL see their last 32°F night by April 7; only one in ten is past it by March 23, and one in ten still has one after April 23. Planting tender crops after April 13 leaves a 30% risk of a frost on them, after April 18 20%, and after April 23 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 26 in half of years, as early as October 14 one year in ten, and holds off past November 9 one year in ten. A hard freeze of 28°F follows 11 days later, around November 6; 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 201 days in a typical year, longer than at 88% of the 158 Illinois stations; it reaches 220 days one year in ten and falls short of 179 one year in ten. On average 99 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 12 days longer, to about April 19, and return around October 17. Severe cold of 16°F or below comes every winter, usually between December 9 and February 26.

July is the warmest month at Fairfield Radio Wfiw, IL, averaging 90°F by day and 68°F at night; January is the coldest at 41°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 69% of years.

Warmth for growing adds up to 4,412 growing degree days a year (base 50°F), more than at 98% of the 158 Illinois stations. 38% of them (1,684) have built up by the end of June, and July adds the most, 890. Precipitation totals 45.9 inches a year, most in April (5.0") and least in February (2.7"); May to September bring 43% of it.

The nearest other station, Albion, IL, 16 miles east of Fairfield, has a last frost 3 days earlier (April 4), a first frost 2 days later (October 28), a season 5 days longer.

The first measurable snow (0.1 inch or more) in Fairfield usually arrives around December 11, and the last of the season around February 25. Those are the middle dates across the winters of 1991–2020 at Fairfield Radio Wfiw, IL, 1.7 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 41 days after the last snow.

ZIP 62837 is 2 miles from Fairfield Radio Wfiw, IL, which stands at 430 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 62837 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.