Last frost date in Ottumwa, Iowa

April 23

Average last frost in spring. In an early year (1 in 10) it's over by April 9; in a late year (1 in 10) it comes after May 7.

October 14

Average first frost in fall. 1 year in 10 it comes by September 29.

Source: NOAA U.S. Climate Normals 1991–2020, station Ottumwa Industrial AP (USW00014950), 6 miles from Ottumwa, elevation 842 ft. NOAA National Centers for Environmental Information. These are long-term averages, not a forecast.

What to plant now

Frost dates for Ottumwa, Iowa
Early yearAverageLate year
Last frost in springApr 9Apr 23May 7
First frost in fallSept 29Oct 14Oct 26

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: 172

Planting calendar for Ottumwa

Fall planting

USDA dates for places whose average first freeze is about October 10 (Ottumwa: October 14).

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 20 (Ottumwa: April 23).

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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