Frost Dates for 61434 — Galva, Illinois

Half of springs at Galva, IL see their last 32°F night by April 26; only one in ten is past it by April 12, and one in ten still has one after May 11. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 5 20%, and after May 11 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 54% of the 158 Illinois stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 12 in half of years, as early as September 25 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 10 days later, around October 22; in spring the one-in-ten date for 28°F is April 30, 11 days before the 32°F one. The freeze-free season lasts 166 days in a typical year, shorter than at 92% of the 158 Illinois stations; it reaches 186 days one year in ten and falls short of 145 one year in ten. On average 137 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 9 days longer, to about May 5, and return around October 2. Severe cold of 16°F or below comes every winter, usually between November 21 and March 15.

July is the warmest month at Galva, IL, averaging 84°F by day and 63°F at night; January is the coldest at 30°F and 13°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 35% of years.

Warmth for growing adds up to 3,123 growing degree days a year (base 50°F), fewer than at 75% of the 158 Illinois stations. 36% of them (1,130) have built up by the end of June, and July adds the most, 728. Precipitation totals 38.7 inches a year, most in June (5.2") and least in January (1.6"); May to September bring 55% of it.

The nearest other station, Kewanee 1 E, IL, 9 miles northeast of Galva, has a last frost 2 days earlier (April 24), a first frost 5 days later (October 17), a season 9 days longer.

The first measurable snow (0.1 inch or more) in Galva usually arrives around December 7, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Galva, IL, 0.2 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 59 days after the last snow.

ZIP 61434 is under a mile from Galva, IL, which stands at 810 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 61434 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.