San Luis, CO 81138 Frost Dates
San Luis, CO: when does the frost end?
The last spring frost here typically falls around 05/28, about 273 days from today. Fall's first freeze usually shows up around 09/21, roughly 115 days after the last spring frost.
San Luis sits in USDA Zone 5a (-20 to -15°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 3 weeks until San Luis's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around San Luis's last frost
05/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/13 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/11 and only about 1 year in 10 sees frost after that.
San Luis against the rest of the dataset
About 115 days separate San Luis's last and first frost, putting it 39,330 of 40,283 ZIP codes nationally. Within CO, it ranks 484 of 624.
Learn more
Before leaning on 81138's figures: the frost range explains how to read the range around San Luis's dates instead of trusting one, while local microclimates explains what one yard in San Luis can differ from the 81138 normal.