Frost Dates for 50212 — Ogden, Iowa

Half of springs at Boone, IA see their last 32°F night by April 28; only one in ten is past it by April 13, and one in ten still has one after May 11. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 11 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 12 in half of years, as early as September 28 one year in ten, and holds off past October 25 one year in ten. A hard freeze of 28°F follows 10 days later, around October 22; in spring the one-in-ten date for 28°F is April 30, 11 days before the 32°F one. The freeze-free season lasts 165 days in a typical year, shorter than at 45% of the 132 Iowa stations; it reaches 185 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 9 days longer, to about May 7, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 17 and March 18.

July is the warmest month at Boone, IA, averaging 84°F by day and 63°F at night; January is the coldest at 28°F and 9°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 38% of years.

Warmth for growing adds up to 3,005 growing degree days a year (base 50°F), more than at 50% of the 132 Iowa stations. 34% of them (1,030) have built up by the end of June, and July adds the most, 727. Precipitation totals 39.3 inches a year, most in June (5.4") and least in January (1.2"); May to September bring 60% of it.

The nearest other station, Ames 8 WSW, IA, 14 miles east of Ogden, has a last frost 5 days earlier (April 23), a first frost 2 days later (October 14), a season 8 days longer.

The first measurable snow (0.1 inch or more) in Ogden usually arrives around November 22, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Boone, IA, 7.9 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 34 days after the last snow.

ZIP 50212 is 8 miles from Boone, IA, which stands at 1,035 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 50036 (Boone). The 2023 USDA Plant Hardiness Zone Map lists ZIP 50212 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.