Frost Dates for 66749 — Iola, Kansas

Half of springs at Iola 1 W, KS see their last 32°F night by April 8; only one in ten is past it by March 25, and one in ten still has one after April 24. Planting tender crops after April 14 leaves a 30% risk of a frost on them, after April 19 20%, and after April 24 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 76% of the 110 Kansas stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 26 in half of years, as early as October 13 one year in ten, and holds off past November 7 one year in ten. A hard freeze of 28°F follows 9 days later, around November 4; in spring the one-in-ten date for 28°F is April 11, 13 days before the 32°F one. The freeze-free season lasts 200 days in a typical year, longer than at 85% of the 110 Kansas stations; it reaches 219 days one year in ten and falls short of 179 one year in ten. On average 106 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 12 days longer, to about April 20, and return around October 18. Severe cold of 16°F or below comes every winter, usually between December 4 and February 28.

July is the warmest month at Iola 1 W, KS, averaging 89°F by day and 69°F at night; January is the coldest at 41°F and 20°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 75% of years.

Warmth for growing adds up to 4,191 growing degree days a year (base 50°F), more than at 62% of the 110 Kansas stations. 36% of them (1,520) have built up by the end of June, and July adds the most, 894. Precipitation totals 42.0 inches a year, most in May (5.8") and least in January (1.3"); May to September bring 58% of it.

The nearest other station, Humboldt, KS, 8 miles south of Iola, has a last frost 3 days later (April 11), a first frost 1 day later (October 27), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Iola usually arrives around December 21, and the last of the season around February 18. Those are the middle dates across the winters of 1991–2020 at Iola 1 W, KS, 1.5 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 49 days after the last snow.

ZIP 66749 is 2 miles from Iola 1 W, KS, which stands at 954 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 66749 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.