Rhinelander, WI 54539 Frost Dates
When can you plant in Rhinelander, WI?
Around 05/19 is the usual last spring frost, about 264 days away. The first fall frost typically arrives around 10/03, about 136 frost-free days later.
Zone 4a (-30 to -25°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Rhinelander, not a forecast for this year.
What to do before the first frost
About 5 weeks of growing season left in Rhinelander before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/19 isn't a guarantee
05/19 is the middle of 30 years of NOAA records, not a promise. Plant by 05/05 and you're betting against frost in roughly 9 years out of 10. 05/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rhinelander compares
About 136 days separate Rhinelander's last and first frost, putting it 37,665 of 40,283 ZIP codes nationally. Within WI, it ranks 751 of 860.
Learn more
local microclimates covers what one yard in Rhinelander can differ from the 54539 normal. zone vs. frost date covers why Zone 4a and Rhinelander's frost date answer different questions.