Sioux Falls, South Dakota – A colder air mass settling over the Northern Plains ahead of St. Patrick’s Day could turn incoming storm systems into accumulating snow across parts of South Dakota between March 11 and March 17.
According to the National Weather Service Climate Prediction Center, South Dakota falls within a 40-50% probability zone for above-normal precipitation during the 8-14 day period. At the same time, temperatures are favored to trend near to below normal statewide, particularly across eastern and northern counties. That combination raises the likelihood that stronger systems produce measurable snowfall instead of chilly rain.
In Sioux Falls, Brookings and Watertown, overnight lows dipping into the 20s could support steady accumulation if moderate precipitation develops. Along Interstate 29 from the North Dakota border south toward Yankton, bursts of heavier snow during pre-dawn hours may reduce visibility and create slick stretches on untreated roads. Farther west toward Pierre and Rapid City, precipitation may begin as rain during daylight hours before mixing with snow at night if colder air deepens.
The broader eastern United States is projected to trend wetter than normal, while California and much of the Southwest remain drier, sharpening the west-to-east contrast in the national pattern.
Travelers across South Dakota should prepare for changing road conditions, especially on open highways where wind can impact visibility. Additional updates are expected as the March 11-17 window approaches and confidence in storm timing increases.
