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Frost dates / Wisconsin / Madison

Frost dates in Madison, WI

The station on this page is UW ARBORETUM - MADISON, WI US (USC00470273), 3.2 miles from the city point. Population in the Census 2024 estimate is 285,300.

Zone 5aUSDA average annual extreme minimum -20°F to -15°F, from ZIP 53792 (0.7 miles from the city point used on this page).

Median last 32°F is May 1. Median first 32°F is October 9. The 50% growing-season length is 161 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.

ProbabilityDateHow to read it
90%April 18Earlier date. A last 32°F on or after this day is common.
50%May 1Median.
10%May 17Later 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.

ProbabilityDateHow to read it
10%September 26Earlier date. A first 32°F on or before this day is uncommon.
50%October 9Median.
90%October 24Later 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 longDays
10%179
50%161
90%140

28°F threshold

10%50%90%
Last, on or afterMay 3April 20April 7
First, on or beforeOctober 5October 20November 3
Season at least202 days182 days163 days

36°F threshold

10%50%90%
Last, on or afterMay 30May 13April 29
First, on or beforeSeptember 17October 1October 12
Season at least159 days139 days119 days

Station UW ARBORETUM - MADISON, WI US (USC00470273). Completeness flag S, 27 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 265.2 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Check a crop against this station

Madison, WI

Zone 5aAverage annual extreme minimum -20°F to -15°F

Median last 32°F is May 1. Median first 32°F is October 9. The 50% growing-season length is 161 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%

Wisconsin. Nearest qualified station: UW ARBORETUM - MADISON, WI US (USC00470273), 3.2 miles. Median last 32°F May 1. Median first 32°F October 9. The 50% growing-season length is 161 days.

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32°F probabilities at this station
10%50%90%
Last 32°F on or afterMay 17May 1April 18
First 32°F on or beforeSeptember 26October 9October 24

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 Wisconsin 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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