Frost Dates for 66523 — Osage City, Kansas

Half of springs at Osage City, KS see their last 32°F night by April 13; only one in ten is past it by March 30, and one in ten still has one after April 28. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 23 20%, and after April 28 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 57% 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 10 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 8 days later, around November 3; in spring the one-in-ten date for 28°F is April 19, 9 days before the 32°F one. The freeze-free season lasts 194 days in a typical year, longer than at 70% of the 110 Kansas stations; it reaches 214 days one year in ten and falls short of 172 one year in ten. On average 124 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 11 days longer, to about April 24, and return around October 15. Severe cold of 16°F or below comes every winter, usually between December 1 and March 3.

July is the warmest month at Osage City, KS, averaging 89°F by day and 67°F at night; January is the coldest at 40°F and 18°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 86% of years.

Warmth for growing adds up to 3,920 growing degree days a year (base 50°F), fewer than at 74% of the 110 Kansas stations. 36% of them (1,405) have built up by the end of June, and July adds the most, 879. Precipitation totals 38.9 inches a year, most in May (5.6") and least in January (0.8"); May to September bring 58% of it.

The nearest other station, Pomona Lake, KS, 15 miles east of Osage City, has a last frost 5 days earlier (April 8), a first frost 5 days later (October 31), a season 11 days longer.

The first measurable snow (0.1 inch or more) in Osage City usually arrives around December 18, and the last of the season around March 3. Those are the middle dates across the winters of 1991–2020 at Osage City, KS, 2.3 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 41 days after the last snow.

ZIP 66523 is 2 miles from Osage City, KS, which stands at 1,094 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 66523 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.