Last frost date in Sioux City, Iowa

April 29

Average last frost in spring. In an early year (1 in 10) it's over by April 15; in a late year (1 in 10) it comes after May 11.

October 7

Average first frost in fall. 1 year in 10 it comes by September 24.

Source: NOAA U.S. Climate Normals 1991–2020, station Sioux City Ang (USC00137702), 6.9 miles from Sioux City, elevation 1,100 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.

What to plant now

Frost dates for Sioux City, Iowa
Early yearAverageLate year
Last frost in springApr 15Apr 29May 11
First frost in fallSept 24Oct 7Oct 21

An early or late year is one in 10: 1 year in 10 the frost comes before the early date, and 1 year in 10 after the late date.

Frost-free days in an average year: 161

Planting calendar for Sioux City

Fall planting

USDA dates for places whose average first freeze is about October 10 (Sioux City: October 7).

USDA lists chervil and chives, garlic, horseradish, leeks, onion plants, onion seed, onion sets, garden peas, shallots as generally spring-planted here.

Spring planting

USDA dates for places whose average last freeze is about April 30 (Sioux City: April 29).

USDA lists chinese cabbage as generally fall-planted here.

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), “Suburban and Farm Vegetable Gardens,” tables 4 and 5 (earliest safe spring and latest safe fall dates), applied to this place's NOAA frost dates. “Plants” means setting out transplants, not sowing seed. How we match the table.

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