Frost Dates for 63383 — Warrenton, Missouri

Half of springs at Warrenton 1 N, MO see their last 32°F night by April 14; only one in ten is past it by March 31, and one in ten still has one after May 3. Planting tender crops after April 22 leaves a 30% risk of a frost on them, after April 27 20%, and after May 3 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 92% of the 158 Missouri stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 23 in half of years, as early as October 9 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 10 days later, around November 2; in spring the one-in-ten date for 28°F is April 18, 15 days before the 32°F one. The freeze-free season lasts 191 days in a typical year, shorter than at 60% of the 158 Missouri stations; it reaches 212 days one year in ten and falls short of 169 one year in ten. On average 111 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 14 days longer, to about April 28, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 4 and March 3.

July is the warmest month at Warrenton 1 N, MO, averaging 88°F by day and 66°F at night; January is the coldest at 39°F and 20°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 88% of years and May still brings one in 14% of years.

Warmth for growing adds up to 3,915 growing degree days a year (base 50°F), fewer than at 65% of the 158 Missouri stations. 37% of them (1,434) have built up by the end of June, and July adds the most, 840.

The nearest other station, Washington, MO, 22 miles southeast of Warrenton and 340 feet lower, has a last frost 6 days earlier (April 8), a first frost 2 days later (October 25), a season 8 days longer.

The first measurable snow (0.1 inch or more) in Warrenton usually arrives around December 29, and the last of the season around February 24. Those are the middle dates across the winters of 1991–2020 at Warrenton 1 N, MO, 2 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 63383 is 2 miles from Warrenton 1 N, MO, which stands at 827 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 63379 (Troy). The 2023 USDA Plant Hardiness Zone Map lists ZIP 63383 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.