Frost Dates for 52342 — Toledo, Iowa

Half of springs at Toledo 3N, IA see their last 32°F night by April 30; only one in ten is past it by April 15, and one in ten still has one after May 11. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 11 10%. The 11 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 9 in half of years, as early as September 26 one year in ten, and holds off past October 22 one year in ten. A hard freeze of 28°F follows 11 days later, around October 20; in spring the one-in-ten date for 28°F is May 3, 8 days before the 32°F one. The freeze-free season lasts 162 days in a typical year, shorter than at 61% of the 132 Iowa stations; it reaches 181 days one year in ten and falls short of 144 one year in ten. On average 152 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 7 days longer, to about May 7, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 15 and March 20.

July is the warmest month at Toledo 3N, IA, averaging 83°F by day and 62°F at night; January is the coldest at 27°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 45% of years.

Warmth for growing adds up to 2,849 growing degree days a year (base 50°F), fewer than at 70% of the 132 Iowa stations. 35% of them (984) have built up by the end of June, and July adds the most, 696. Precipitation totals 35.3 inches a year, most in June (5.6") and least in January (1.0"); May to September bring 62% of it.

The nearest other station, Belle Plaine, IA, 18 miles southeast of Toledo, has a last frost 2 days earlier (April 28), a first frost 1 day later (October 10), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Toledo 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 Toledo 3N, 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 36 days after the last snow.

ZIP 52342 is under a mile from Toledo 3N, IA, which stands at 935 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 52339 (Tama). The 2023 USDA Plant Hardiness Zone Map lists ZIP 52342 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.