Frost Dates for 66087 — Troy, Kansas

Half of springs at Troy 3N, KS see their last 32°F night by April 19; only one in ten is past it by April 4, and one in ten still has one after May 5. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 30 20%, and after May 5 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 19 in half of years, as early as October 2 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 10 days later, around October 29; in spring the one-in-ten date for 28°F is April 25, 10 days before the 32°F one. The freeze-free season lasts 182 days in a typical year, shorter than at 67% of the 110 Kansas stations; it reaches 203 days one year in ten and falls short of 160 one year in ten. On average 121 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 10 days longer, to about April 29, and return around October 8. Severe cold of 16°F or below comes every winter, usually between November 26 and March 8.

July is the warmest month at Troy 3N, KS, averaging 87°F by day and 67°F at night; January is the coldest at 36°F and 17°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 18% of years.

Warmth for growing adds up to 3,760 growing degree days a year (base 50°F), fewer than at 87% of the 110 Kansas stations. 36% of them (1,358) have built up by the end of June, and July adds the most, 832. Precipitation totals 37.0 inches a year, most in May (5.1") and least in January (1.0"); May to September bring 59% of it.

The nearest other station, St Joseph Rosecrans Airport, MO, 11 miles east of Troy and 222 feet lower, has the same 50% last-frost date, a first frost 2 days earlier (October 17), a season 2 days shorter.

The first measurable snow (0.1 inch or more) in Troy usually arrives around December 1, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Troy 3N, KS, 3.1 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 29 days after the last snow.

ZIP 66087 is 3 miles from Troy 3N, KS, which stands at 1,040 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 66087 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.