Siren, WI 54872 Frost Dates
Siren, WI: when does the frost end?
Typically, the last spring freeze lands around 05/11, roughly 256 days out. Fall's first freeze usually shows up around 10/01, roughly 141 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Siren in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 5 weeks until Siren's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Siren's last frost
05/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/28 and only about 1 year in 10 sees frost after that.
Siren against the rest of the dataset
About 141 days separate Siren's last and first frost, putting it 36,948 of 40,283 ZIP codes nationally. Within WI, it ranks 708 of 860.
Learn more
Before leaning on 54872's figures: local microclimates explains what one yard in Siren can differ from the 54872 normal, while zone vs. frost date explains why Zone 4b and Siren's frost date answer different questions.