When Does South Dakota Get Its First Frost?

Winter in South Dakota can sneak up on ya. We'll be having a nice mild fall then BAM, it's cold and snowy.

One of the first signs of the seasons changing is when we get our first frost. The way that Labor Day is the unofficial end of summer, our first frost is the unofficial end of the summer growing season.

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The first frost of the year is the day when the temperature, especially early in the morning, drops to freezing (32°F/0°C). When that happens plants outside can get damaged. This is the day to start bringing the plants inside, or to pick those tomatoes and peppers.

When Might Frost Come Early or Late?

The Old Farmer’s Almanac makes predictions for when the first frost will sweep across the state. They make their calculations on past events and statistical averages. But, as with all predications, they may not be exact.

South Dakota is home to many variations in climate that make the average first frost of the year happen at different times. While most of the state usually sees its first frost at the end of September. The elevation and how far north you are make big differences.

📍 City‑by‑City First Frost Dates

For example, Sioux Falls in the southeastern part of the state has its first frost on September 30.

A little further south, right along the Nebraska border, Yankton usually get its on October 3.

When you get up north, near North Dakota, in a place like Aberdeen, the first frost is usually a bit earlier, September 24. Same with Brookings.

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Right smack in the middle of the state, Chamberlin, SD get its first frost on October 1. Pierre usually get its on September 28.

How Elevation Affects Frost Timing

As we move to the west we start climbing in elevation. Both because we are in the very beginnings of the foothills of the Rockies west of SD, but also because of our own little mountain range, The Black Hills.

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For comparison, Sioux Falls is 1463 feet above sea-level, while five hours west in Rapid City, they sit at 3202 feet above sea-level. As you get into the Black Hills, Custer is at 5315 feet. That about 100 feet higher than the Mile High City, Denver, Colorado.

Right on the eastern edge of The Hills sits Rapid City. There the first frost is October 1.

As we go up into the Hills, Custer get their first frost nearly 10 days sooner than Sioux Falls, on September 21. Sturgis get theirs on September 28, and Spearfish on the 29th.

As always, remember that these are predictions based on past events. The first frost can come earlier or later. But as a rule of thumb, if you live in South Dakota you will get your first frost by the end of September/beginning of October.