South Dakota’s Fall 2025 Forecast: What to Expect

If you're making plans for fall activities in South Dakota this autumn, you're going to be keeping an eye on the weather. Here's the fall weather forecast from The Old Farmer’s Almanac: cooler temperatures in September and October with just above average precipitation. Classic South Dakota fall weather, perfect for football, pumpkin patches, and other autumn fun.

READ MORE: South Dakota High School Football Week 1 Schedules

How Does The Old Farmer's Almanac Predict the Weather?

The Old Farmer's Almanac was first published in 1792. The Almanac has been a go-to for weather, gardening, and other information since George Washington was a farmer.

In the days before the internet or even easily accessible libraries, the Almanac was one of the only ways to get some of this info. Like when to plant what, how to deal with garden pests, and the weather.

Several times a year, The Old Farmer's Almanac puts out long-range weather forecasts based on a formula devised by its founder, Robert B. Thomas, combined with folklore and modern science. They say they have an 80% hit rate, so maybe taking into account the thickness of corn husks, like grandpa used to say, meant a hard winter, works.

"Thomas believed the Earth’s weather was influenced by sunspots, which are magnetic storms on the surface of the Sun, and this factored heavily in his forecasts," The Almanac says.

How Accurate Is The Old Farmer’s Almanac?

Last year, for fall 2024, The Old Farmer's Almanac said we'd have a warm and dry autumn. From what I remember, that is pretty right on. They stick to broad, general predictions, but still it's still a good guide for planning.

The Old Farmer's Almanac Fall 2025 Forecast for South Dakota

When it comes to the fall forecast for South Dakota, The Old Farmer's Almanac has the state sliced up.

The forecast for West River, South Dakota, is warm and wet with "...warmer than usual in September, then trend closer to normal in October." In September, the west will be mostly sunny with a cooldown and storms in the middle of the month.

And in October, average temperatures are expected, with cooler days with storms mid-month before a warm-up going into November.

What to Expect in East River This Fall

For East River, South Dakota, including the Sioux Falls area, they say "September and October will be cooler and drier than normal overall."

September temperatures are predicted to be slightly below average, with precipitation just above average. "Expect frequent rain, drizzle, and some early snow in the north," the Almanac's forecast says.

October in eastern South Dakota looks to be chilly and wet, with a brief warm-up in the middle of the month.

READ MORE: South Dakota Split: 5 Big Differences Between East and West River

Planning Fall Events? Here’s What to Know

Sounds to me like another basic autumn in South Dakota. Warm then cool with some rain and maybe a bit of snow.