Jefferson, WI 53549 Frost Dates
When can you plant in Jefferson, WI?
Around 04/25 is the usual last spring frost, about 240 days away. The first fall frost typically arrives around 10/18, about 173 frost-free days later.
The USDA Plant Hardiness Zone Map puts Jefferson in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 7 weeks of growing season left in Jefferson before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/25 is the middle of 30 years of NOAA records, not a promise. Plant by 04/12 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Jefferson compares
Jefferson's growing season runs about 173 days, ranking 27,831 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 109 of 860.
Learn more
local microclimates covers what one yard in Jefferson can differ from the 53549 normal. zone vs. frost date covers why Zone 5b and Jefferson's frost date answer different questions.