Frost dates / Michigan / Flint

Frost dates in Flint, MI

The station on this page is FLINT 7W, MI US (USC00202851), 4 miles from the city point. Population in the Census 2024 estimate is 79,735.

Zone 6aUSDA average annual extreme minimum -10°F to -5°F, from ZIP 48502 (0.7 miles from the city point used on this page).

Median last 32°F is May 3. Median first 32°F is October 13. The 50% growing-season length is 162 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%	April 20	Earlier date. A last 32°F on or after this day is common.
50%	May 3	Median.
10%	May 20	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%	September 30	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 13	Median.
90%	October 27	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%	181
50%	162
90%	142

28°F threshold

	10%	50%	90%
Last, on or after	May 9	April 22	April 8
First, on or before	October 12	October 27	November 9
Season at least	206 days	186 days	163 days

36°F threshold

	10%	50%	90%
Last, on or after	May 29	May 14	April 29
First, on or before	September 20	October 2	October 13
Season at least	159 days	141 days	122 days

Station FLINT 7W, MI US (USC00202851). Completeness flag R, 15 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 207 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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Flint, MI

Zone 6aAverage annual extreme minimum -10°F to -5°F

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

Michigan. Nearest qualified station: FLINT 7W, MI US (USC00202851), 4 miles. Median last 32°F May 3. Median first 32°F October 13. The 50% growing-season length is 162 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	May 20	May 3	April 20
First 32°F on or before	September 30	October 13	October 27

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 Michigan 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.

Date checks use your device’s calendar and appear after the page loads.