Frost Dates for 50536 — Emmetsburg, Iowa

Half of springs at Emmetsburg, IA see their last 32°F night by April 27; only one in ten is past it by April 11, and one in ten still has one after May 9. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 4 20%, and after May 9 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 22 one year in ten. A hard freeze of 28°F follows 13 days later, around October 20; in spring the one-in-ten date for 28°F is April 30, 9 days before the 32°F one. The freeze-free season lasts 164 days in a typical year, shorter than at 52% of the 132 Iowa stations; it reaches 184 days one year in ten and falls short of 146 one year in ten. On average 153 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 8 days longer, to about May 5, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 15 and March 22.

July is the warmest month at Emmetsburg, IA, averaging 85°F by day and 63°F at night; January is the coldest at 26°F and 7°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 3,001 growing degree days a year (base 50°F), fewer than at 51% of the 132 Iowa stations. 35% of them (1,040) have built up by the end of June, and July adds the most, 745. Precipitation totals 33.7 inches a year, most in June (5.5") and least in January (0.7"); May to September bring 64% of it.

The nearest other station, Estherville 4E, IA, 20 miles north of Emmetsburg, has a last frost 5 days later (May 2), a first frost 4 days earlier (October 3), a season 11 days shorter.

The first measurable snow (0.1 inch or more) in Emmetsburg usually arrives around November 18, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Emmetsburg, IA, 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 21 days after the last snow.

ZIP 50536 is 1 mile from Emmetsburg, IA, which stands at 1,225 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 50536 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.