Madison, WI Frost Dates: Last Spring and First Fall Frost

In a typical year the final freeze of spring reaches Madison around May 1, and the first freeze of autumn returns around October 9. NOAA's normals call the frost-free stretch between them 161 days long.

Dates at even odds leave half of all years unprotected. The safer pair for Madison is May 17 in spring, which only one year in ten passes, and September 26 in fall, which one year in ten arrives before. The median season across the 100 cities on these pages is 229 days; Madison comes up 68 days short of it, 95th on the list.

Behind every date on this page is one weather station, Uw Arboretum - Madison (NOAA USC00470273), 3.2 miles south of Madison's internal point in the Census Bureau's files and about 870 feet up.

When is the last frost in Madison?

One year in ten has a freeze on or after May 17. In nine years out of ten there is still a freeze on or after April 18, and half of years see one on or after May 1.

The early and late dates sit just 29 days apart, narrower than for most cities on these pages. Spring in Madison rarely surprises by much.

Madison's first fall frost, by chance

In Madison the first freeze has arrived by September 26 in one fall out of ten, by October 9 in five, and by October 24 in nine.

Just 28 days separate the early and late dates, tighter than most cities on these pages.

How long is the frost-free season in Madison?

Madison has far fewer frost-free days than the middle of these pages, so slow crops are the ones squeezed, as the planting dates below show. There is little difference between a typical season (161 days) and a short one (140 days) in Madison: 21 days, less than in most of the cities covered here.

The season lengths come from NOAA's simulated years, not from subtracting one typical date from the other, so the two will not match to the day. At Uw Arboretum - Madison a night at or below 32°F turns up in 100% of years, which means these dates apply every winter.

Hard freeze dates for Madison

Between a light frost and a hard freeze there is little room in Madison: the typical 28°F dates are October 20 and April 20, just 11 days and 11 days from the 32°F dates. The late 28°F spring date, May 3, is the one that still catches blooms and young transplants one year in ten, and the early fall date, October 5, is when a hard freeze has arrived in one fall out of ten.

Using Madison's frost dates in the garden

The University of New Hampshire Extension sheet times each crop from the last frost. For Madison's typical date, May 1, that means cabbage on April 3, lettuce from April 3 to April 10, seed potatoes from April 17 to April 24, and, once the frost is behind you, peppers on May 15 and beans on or after May 1. Peas are the exception to the count: University of New Hampshire Extension says to plant them as soon as the soil thaws, whatever the frost date.

Counting from the late date, May 17, instead of the typical one delays every after-frost crop by 16 days. That is the price of a one-in-ten spring that most years will not need.

Fall crops are counted back from the first frost, using NC State Extension's days to harvest plus University of Georgia Extension's harvest allowance of 18 days. In Madison only 20 of the 34 crops in the fall planner have a last planting day in July or later, and the other 14 would have to go in before then, in spring or early summer. Of the crops that fit, cauliflower is the slowest: 83 days from planting to the early frost, which makes July 5 its last day.

Worked example: setting out tomatoes in Madison

Take tomatoes in Madison. The University of New Hampshire Extension rule is to set transplants out one to two weeks after the last frost. From May 1, the typical date, that means May 8 to May 15; from May 17, the late date, it means May 24 to May 31, a delay of 16 days.

Indoors, tomato seeds go in six to eight weeks ahead of set-out; from the first day of the late window that is March 29 to April 12.

From the last set-out day to the early first frost on September 26 is 118 days. NC State Extension gives 75 to 85 days, and the longer figure still fits with 33 days to spare.

About the Uw Arboretum - Madison station

The station is 3.2 miles south of the Census Bureau's internal point for Madison, near enough to be the city's reference record, though not in the same yard.

Its elevation is about 870 feet. Of the 100 stations behind these pages, 33 sit higher and 66 lower. In NOAA's file the record is marked S, meaning standard.

The Census Gazetteer gives no elevation for Madison itself, so this page cannot tell you whether your garden sits above or below the station. If it is noticeably higher or lower, compare the stations the frost dates tool lists nearby and lean toward the colder reading.

How Madison's frost dates compare

Here is how Madison, with a last frost on May 1 and a first frost on October 9, compares with the three nearest cities on these pages, the closest being Milwaukee, WI at 74 miles.

• Milwaukee, WI, 74 miles to the east: last frost April 26, first frost October 18, 173 days frost-free; spring frost ends 5 days sooner than in Madison, and the season runs 12 days longer.
• Chicago, IL lies 124 miles south-east of Madison. Typical last frost April 10, first frost November 5, 208 days between; its last frost comes 21 days before Madison's, and it has 47 days more without frost.
• St. Paul, MN lies 223 miles north-west of Madison. Typical last frost April 24, first frost October 16, 174 days between; the last frost is 7 days earlier than in Madison, and the frost-free season is 13 days longer than Madison's.

Take these dates further

Start with the spring planting planner for the whole crop list counted from these dates, and the fall planting planner for the last planting days. The frost dates tool shows every level of risk at this station, and the hardiness zone lookup covers winter survival for shrubs and perennials.

Looking for another city? The city frost dates index lists every page, grouped by state.

Where these numbers come from

The frost and freeze dates are NOAA's U.S. Climate Normals for 1991–2020 (doi:10.25921/4ek7-fk11), copied from the station's own record without adjustment; NOAA's documentation defines each probability. The Census Bureau's 2024 Gazetteer places Madison on the map, and its Vintage 2024 estimates, 285,300 people here, decide which cities get a page.

University of New Hampshire Extension, NC State Extension and University of Georgia Extension supply the planting rules; this page only counts them from the station's dates. See how we source every figure for the checks behind them.

These dates describe odds over many years, not next week's weather. Look at the forecast before you plant, and keep a sheet or row cover ready for a night that does not follow the odds.