Frost Dates for 52057 — Manchester, Iowa

Half of springs at Manchester #2, IA see their last 32°F night by May 3; only one in ten is past it by April 18, and one in ten still has one after May 16. Planting tender crops after May 9 leaves a 30% risk of a frost on them, after May 12 20%, and after May 16 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 42% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 4 in half of years, as early as September 22 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 11 days later, around October 15; in spring the one-in-ten date for 28°F is May 7, 9 days before the 32°F one. The freeze-free season lasts 154 days in a typical year, shorter than at 84% of the 132 Iowa stations; it reaches 174 days one year in ten and falls short of 136 one year in ten. On average 158 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 12, and return around September 26. Severe cold of 16°F or below comes every winter, usually between November 14 and March 21.

July is the warmest month at Manchester #2, IA, averaging 82°F by day and 61°F at night; January is the coldest at 26°F and 8°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 60% of years.

Warmth for growing adds up to 2,660 growing degree days a year (base 50°F), fewer than at 89% of the 132 Iowa stations. 34% of them (917) have built up by the end of June, and July adds the most, 668. Precipitation totals 38.5 inches a year, most in June (6.0") and least in January (1.1"); May to September bring 60% of it.

The nearest other station, Coggon, IA, 15 miles south of Manchester, has the same 50% last-frost date, a first frost 3 days later (October 7), a season 2 days longer.

The first measurable snow (0.1 inch or more) in Manchester usually arrives around November 19, and the last of the season around April 7. Those are the middle dates across the winters of 1991–2020 at Manchester #2, IA, 0.8 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 26 days after the last snow.

ZIP 52057 is under a mile from Manchester #2, IA, which stands at 990 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 52057 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.