Frost Dates for 64601 — Chillicothe, Missouri

Half of springs at Chillicothe 2S, MO see their last 32°F night by April 15; only one in ten is past it by April 1, and one in ten still has one after April 30. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 25 20%, and after April 30 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 54% of the 158 Missouri stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 21 in half of years, as early as October 7 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around November 1; in spring the one-in-ten date for 28°F is April 19, 11 days before the 32°F one. The freeze-free season lasts 187 days in a typical year, shorter than at 73% of the 158 Missouri stations; it reaches 206 days one year in ten and falls short of 165 one year in ten. On average 123 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 26, and return around October 11. Severe cold of 16°F or below comes every winter, usually between November 29 and March 7.

July is the warmest month at Chillicothe 2S, MO, averaging 87°F by day and 67°F at night; January is the coldest at 35°F and 16°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 3,699 growing degree days a year (base 50°F), fewer than at 82% of the 158 Missouri stations. 36% of them (1,331) have built up by the end of June, and July adds the most, 843. Precipitation totals 41.3 inches a year, most in May (5.4") and least in January (1.3"); May to September bring 59% of it.

The nearest other station, Trenton, MO, 20 miles north of Chillicothe, has a last frost 1 day later (April 16), a first frost 1 day earlier (October 20), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Chillicothe usually arrives around December 8, and the last of the season around March 5. Those are the middle dates across the winters of 1991–2020 at Chillicothe 2S, MO, 1.2 miles away: half of years saw snow earlier, half later. Snow fell in 97% of those winters. The last 32°F night of spring typically comes 41 days after the last snow.

ZIP 64601 is 1 mile from Chillicothe 2S, MO, which stands at 780 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 64601 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.