Frost Dates for 63549 — La Plata, Missouri

Half of springs at Kirksville Regional Airport, MO see their last 32°F night by April 19; only one in ten is past it by April 5, and one in ten still has one after May 5. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after May 1 20%, and after May 5 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 35% of the 158 Missouri stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 1 one year in ten, and holds off past October 31 one year in ten. A hard freeze of 28°F follows 11 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 180 days in a typical year, shorter than at 89% of the 158 Missouri stations; it reaches 200 days one year in ten and falls short of 157 one year in ten. On average 125 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 May 1, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 24 and March 9.

July is the warmest month at Kirksville Regional Airport, MO, averaging 86°F by day and 65°F at night; January is the coldest at 34°F and 17°F. A freezing night is all but certain in every month from October 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 20% of years.

Warmth for growing adds up to 3,447 growing degree days a year (base 50°F), fewer than at 96% of the 158 Missouri stations. 36% of them (1,232) have built up by the end of June, and July adds the most, 787. Precipitation totals 39.3 inches a year, most in June (5.1") and least in January (1.6"); May to September bring 56% of it.

The nearest other station, Kirksville, MO, 13 miles north of La Plata, has a last frost 2 days later (April 21), a first frost 1 day later (October 19), a season 1 day shorter.

The first measurable snow (0.1 inch or more) in La Plata usually arrives around December 7, and the last of the season around March 11. Those are the middle dates across the winters of 1991–2020 at Kirksville, MO, 13.5 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 39 days after the last snow.

ZIP 63549 is 6 miles from Kirksville Regional Airport, MO, which stands at 966 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 63549 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.