Frost Dates for 50648 — Jesup, Iowa

Half of springs at Independence #1, IA see their last 32°F night by April 30; only one in ten is past it by April 16, and one in ten still has one after May 12. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 8 20%, and after May 12 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 7 in half of years, as early as September 23 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 10 days later, around October 17; in spring the one-in-ten date for 28°F is May 4, 8 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, shorter than at 73% of the 132 Iowa stations; it reaches 178 days one year in ten and falls short of 141 one year in ten. On average 151 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 9, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 14 and March 22.

July is the warmest month at Independence #1, IA, averaging 83°F by day and 62°F at night; January is the coldest at 27°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 47% of years.

Warmth for growing adds up to 2,856 growing degree days a year (base 50°F), fewer than at 68% of the 132 Iowa stations. 35% of them (995) have built up by the end of June, and July adds the most, 694. Precipitation totals 37.5 inches a year, most in June (5.7") and least in January (1.0"); May to September bring 61% of it.

The nearest other station, Oelwein 2 S, IA, 16 miles northeast of Jesup, has the same 50% last-frost date, a first frost 2 days later (October 9), a season 4 days longer.

The first measurable snow (0.1 inch or more) in Jesup usually arrives around November 23, and the last of the season around April 3. Those are the middle dates across the winters of 1991–2020 at Independence #1, IA, 12.1 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 27 days after the last snow.

ZIP 50648 is 12 miles from Independence #1, IA, which stands at 1,010 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 50644 (Independence). The 2023 USDA Plant Hardiness Zone Map lists ZIP 50648 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.