Frost Dates for 65109 — Jefferson City, Missouri

Half of springs at Jefferson City Wtp, MO see their last 32°F night by April 8; only one in ten is past it by March 23, and one in ten still has one after April 23. Planting tender crops after April 14 leaves a 30% risk of a frost on them, after April 18 20%, and after April 23 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 31 in half of years, as early as October 17 one year in ten, and holds off past November 11 one year in ten. A hard freeze of 28°F follows 8 days later, around November 8; in spring the one-in-ten date for 28°F is April 13, 10 days before the 32°F one. The freeze-free season lasts 205 days in a typical year, longer than at 83% of the 158 Missouri stations; it reaches 225 days one year in ten and falls short of 186 one year in ten. On average 106 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 13 days longer, to about April 21, and return around October 21. Severe cold of 16°F or below comes every winter, usually between December 12 and February 28.

July is the warmest month at Jefferson City Wtp, MO, averaging 88°F by day and 69°F at night; January is the coldest at 40°F and 21°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 73% of years.

Warmth for growing adds up to 4,107 growing degree days a year (base 50°F), more than at 58% of the 158 Missouri stations. 36% of them (1,490) have built up by the end of June, and July adds the most, 877. Precipitation totals 43.5 inches a year, most in May (5.2") and least in January (2.2"); May to September bring 51% of it.

The nearest other station, Jefferson City Mem Airport, MO, 5 miles east of Jefferson City, has a last frost 2 days later (April 10), a first frost 5 days earlier (October 26), a season 7 days shorter.

The first measurable snow (0.1 inch or more) in Jefferson City usually arrives around December 11, and the last of the season around February 13. Those are the middle dates across the winters of 1991–2020 at Jefferson City Wtp, MO, 4 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 54 days after the last snow.

ZIP 65109 is 4 miles from Jefferson City Wtp, MO, which stands at 650 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 65109 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.