Frost Dates for 52031 — Bellevue, Iowa

Half of springs at Bellevue L&D 12, IA see their last 32°F night by April 25; only one in ten is past it by April 10, 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 16 days between the even-odds date and the one-in-ten date is wider than at 95% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 1 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 27; in spring the one-in-ten date for 28°F is May 2, 9 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, longer than at 73% of the 132 Iowa stations; it reaches 194 days one year in ten and falls short of 152 one year in ten. On average 146 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 10 days longer, to about May 5, and return around October 5. Severe cold of 16°F or below comes every winter, usually between November 25 and March 14.

July is the warmest month at Bellevue L&D 12, IA, averaging 85°F by day and 63°F at night; January is the coldest at 29°F and 12°F. A freezing night is all but certain in every month from October 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 35% of years.

Warmth for growing adds up to 3,021 growing degree days a year (base 50°F), more than at 52% of the 132 Iowa stations. 34% of them (1,022) have built up by the end of June, and July adds the most, 733. Precipitation totals 37.9 inches a year, most in June (5.6") and least in January (1.3"); May to September bring 57% of it.

The nearest other station, Galena, IL, 11 miles northeast of Bellevue and 219 feet higher, has a last frost 1 day later (April 26), a first frost 1 day earlier (October 15), a season 2 days shorter.

The first measurable snow (0.1 inch or more) in Bellevue usually arrives around December 3, and the last of the season around March 17. Those are the middle dates across the winters of 1991–2020 at Bellevue L&D 12, IA, 2.6 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 39 days after the last snow.

ZIP 52031 is 3 miles from Bellevue L&D 12, IA, which stands at 603 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 52031 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.