Frost dates / Missouri / Wentzville

Frost dates in Wentzville, MO

The station on this page is WELDON SPRING NWS, MO US (USC00238805), 13 miles from the city point. Population in the Census 2024 estimate is 48,646.

Zone 6bUSDA average annual extreme minimum -5°F to 0°F, from ZIP 63385 (1.5 miles from the city point used on this page).

Median last 32°F is April 10. Median first 32°F is October 26. The 50% growing-season length is 199 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	March 26	Earlier date. A last 32°F on or after this day is common.
50%	April 10	Median.
10%	April 26	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	October 12	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 26	Median.
90%	November 8	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	220
50%	199
90%	178

28°F threshold

	10%	50%	90%
Last, on or after	April 15	March 31	March 12
First, on or before	October 22	November 5	November 22
Season at least	242 days	221 days	199 days

36°F threshold

	10%	50%	90%
Last, on or after	May 6	April 22	April 8
First, on or before	October 1	October 16	October 28
Season at least	196 days	176 days	155 days

Station WELDON SPRING NWS, MO US (USC00238805). Completeness flag S, 29 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 185.9 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

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Wentzville, MO

Zone 6bAverage annual extreme minimum -5°F to 0°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Missouri. Nearest qualified station: WELDON SPRING NWS, MO US (USC00238805), 13 miles. Median last 32°F April 10. Median first 32°F October 26. The 50% growing-season length is 199 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	April 26	April 10	March 26
First 32°F on or before	October 12	October 26	November 8

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

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Planting calendar

Frost dates for Missouri are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

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