Frost Dates for 50574 — Pocahontas, Iowa

Half of springs at Pocahontas, IA see their last 32°F night by April 26; only one in ten is past it by April 11, and one in ten still has one after May 8. Planting tender crops after May 2 leaves a 30% risk of a frost on them, after May 4 20%, and after May 8 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 25 one year in ten, and holds off past October 20 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 April 30, 8 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 181 days one year in ten and falls short of 144 one year in ten. On average 157 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 5, and return around September 28. Severe cold of 16°F or below comes every winter, usually between November 13 and March 21.

July is the warmest month at Pocahontas, IA, averaging 84°F by day and 62°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 35% of years.

Warmth for growing adds up to 2,942 growing degree days a year (base 50°F), fewer than at 58% of the 132 Iowa stations. 35% of them (1,034) have built up by the end of June, and July adds the most, 724. Precipitation totals 32.7 inches a year, most in June (4.7") and least in January (1.0"); May to September bring 62% of it.

The nearest other station, Rockwell City, IA, 23 miles south of Pocahontas, has the same 50% last-frost date, a first frost 3 days later (October 10), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Pocahontas usually arrives around November 11, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Pocahontas, IA, 1.2 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 20 days after the last snow.

ZIP 50574 is 1 mile from Pocahontas, IA, which stands at 1,212 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 50574 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.