Castleford, ID 83321 Frost Dates
Castleford, ID: when does the frost end?
The last spring frost here typically falls around 05/17, about 262 days from today. Fall's first freeze usually shows up around 09/29, roughly 132 days after the last spring frost.
Castleford sits in USDA Zone 6b (-5 to 0°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
With roughly 5 weeks until Castleford'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
05/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/05 and only about 1 year in 10 sees frost after that.
Castleford against the rest of the dataset
About 132 days separate Castleford's last and first frost, putting it 38,228 of 40,283 ZIP codes nationally. Within ID, it ranks 170 of 320.
Learn more
Before leaning on 83321's figures: the frost range explains how to read the range around Castleford's dates instead of trusting one, while local microclimates explains what one yard in Castleford can differ from the 83321 normal.