Frost Dates for 52537 — Bloomfield, Iowa

Half of springs at Bloomfield, IA see their last 32°F night by April 16; only one in ten is past it by April 1, and one in ten still has one after April 30. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 26 20%, and after April 30 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 58% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as October 5 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 9 days later, around October 31; in spring the one-in-ten date for 28°F is April 20, 10 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, longer than at 95% of the 132 Iowa stations; it reaches 207 days one year in ten and falls short of 166 one year in ten. On average 128 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 28, and return around October 11. Severe cold of 16°F or below comes every winter, usually between November 28 and March 10.

July is the warmest month at Bloomfield, IA, averaging 86°F by day and 66°F at night; January is the coldest at 32°F and 15°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 10% of years.

Warmth for growing adds up to 3,456 growing degree days a year (base 50°F), more than at 92% of the 132 Iowa stations. 35% of them (1,208) have built up by the end of June, and July adds the most, 803. Precipitation totals 39.1 inches a year, most in May (5.5") and least in January (1.2"); May to September bring 62% of it.

The nearest other station, Centerville, IA, 23 miles west of Bloomfield, has a last frost 12 days later (April 28), a first frost 8 days earlier (October 14), a season 20 days shorter.

The first measurable snow (0.1 inch or more) in Bloomfield usually arrives around November 22, and the last of the season around March 19. Those are the middle dates across the winters of 1991–2020 at Bloomfield, IA, 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 28 days after the last snow.

ZIP 52537 is 2 miles from Bloomfield, IA, which stands at 858 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 52537 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.