Bristow, IA 50611 Frost Dates
Bristow, IA: when does the frost end?
The last spring frost here typically falls around 04/30, about 245 days from today. Fall's first freeze usually shows up around 10/06, roughly 157 days after the last spring frost.
Zone 5a (-20 to -15°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 Bristow, not a forecast for this year.
Stretching the season past the first frost
With roughly 6 weeks until Bristow's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Bristow against the rest of the dataset
At roughly 157 frost-free days, Bristow places 33,461 of 40,283 ZIP codes in this dataset. Within IA, it ranks 856 of 1,042.
Learn more
Before leaning on 50611's figures: zone vs. frost date explains why Zone 5a and Bristow's frost date answer different questions, while the frost range explains how to read the range around Bristow's dates instead of trusting one.