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Frost dates for Madison Dane Regional Airport, Wisconsin

Half of years have their last spring frost by May 1, but 1 year in 10 still frosts after May 16.

A frost date is really a percentile from 30 years of records at a nearby weather station: in about half of years a frost still comes after the median date. Both numbers are below, so you can choose the risk yourself.

The odds

Last spring frost

How often a frost still comes on or after each date.

1 year in 10
May 16
1 year in 5
May 11
3 years in 10
May 7
2 years in 5
May 3
Half of years (the median)
May 1

First fall freeze

How often the first freeze comes on or before each date.

1 year in 10
September 26
1 year in 5
September 30
3 years in 10
October 4
2 years in 5
October 7
Half of years (the median)
October 10
Growing season
about 160 days
Hardiness zones nearby
5a, 5b
Summer days
a usual high of about 27 °C80 °F
Lettuce and spinach run to seed
June to August, in hot, long days (how we know)

Summer and rain

A growing garden needs about 25 mm1 in of water a week, rain and watering together. Here is what a normal month brings.

Month by month

January
high ~-3 °C27 °F · low ~-11 °C12 °F · rain ~37 mm1.5 in
February
high ~0 °C31 °F · low ~-10 °C15 °F · rain ~39 mm1.5 in
March
high ~6 °C44 °F · low ~-4 °C25 °F · rain ~57 mm2.3 in
April
high ~14 °C57 °F · low ~2 °C36 °F · rain ~96 mm3.8 in
May
high ~21 °C69 °F · low ~8 °C47 °F · rain ~104 mm4.1 in
June
high ~26 °C79 °F · low ~14 °C57 °F · rain ~134 mm5.3 in
July
high ~28 °C82 °F · low ~16 °C62 °F · rain ~115 mm4.5 in
August
high ~27 °C80 °F · low ~15 °C60 °F · rain ~106 mm4.2 in
September
high ~23 °C73 °F · low ~11 °C51 °F · rain ~87 mm3.4 in
October
high ~15 °C60 °F · low ~4 °C40 °F · rain ~70 mm2.8 in
November
high ~7 °C45 °F · low ~-2 °C29 °F · rain ~56 mm2.2 in
December
high ~0 °C32 °F · low ~-8 °C18 °F · rain ~41 mm1.6 in

Where these numbers come from

NOAA NCEI 1991–2020 Climate Normals, the Madison Dane Regional Airport station (listed by NOAA as Madison Dane Rgnl Ap, USW00014837), at 43.14, -89.35. These are that station’s own records, unshifted. The further your garden is from it, the less exactly they describe your ground. The planner finds the nearest station to your garden and lowers its confidence with distance, so no number is presented as if it were measured in your garden.

Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a few hundred feet away does not. No table can know that about your garden. A few seasons of your own logged frosts can.

ZIP codes nearest this station

53521, 53523, 53527, 53529, 53531, 53532, 53558, 53559, 53562, 53571, 53575, 53589, 53590, 53593, 53597, 53598, 53703, 53704, 53705, 53706, 53711, 53713, 53714, 53715, 53716, 53717, 53718, 53719, 53726, 53792, 53911, 53925.

What can I plant here, and when? ›

Nearby stations

The nearest stations and how their last-frost dates compare. Together they show how frost varies across your area.

All locations · All plants · Folklore, checked