If you’re planning a trip to South Dakota around Labor Day, get ready for late-summer weather that feels warm during the day but cools off at night. Daytime highs usually land in the low to mid-20s °C (70s °F), while nighttime lows often drop into the low teens °C (50s °F). This mix of comfortable warmth and crisp evenings makes early September a great time to visit.
Weather depends a lot on where you go. Eastern spots like Sioux Falls often feel a bit warmer and more humid. Out west, places like Rapid City stay drier, and nights get cooler. Skies are often clear or just partly cloudy, and you still get plenty of daylight—just without the intense midsummer heat.
You’ll notice that mild temperatures, moderate chances for rain, and steady breezes set the scene for hiking, sightseeing, or taking in local events. Whether you’re wandering the Black Hills or hanging out at a small-town festival, knowing what weather to expect really helps you make the most of the long weekend.
Labor Day Weather Overview in South Dakota
Early September in South Dakota brings warm days and cool nights. Rain can happen, but the weather varies a lot—some years bring heat, storms, or even a surprise snow.
Typical Temperature Ranges
Around Labor Day, South Dakota usually sees highs in the 70s to mid-80s °F (21–29°C). Some years, afternoons heat up into the upper 80s or low 90s °F (31–33°C), especially out west near Rapid City.
Evenings cool off fast. Lows often fall into the 50s °F (10–15°C), and the Black Hills can get even chillier at night. You’ll notice mornings feel crisp compared to the afternoon.
Warm days and cool nights signal that summer’s winding down. If you’re traveling, pack light clothes for daytime and a jacket for the evenings.
Precipitation Patterns
Labor Day rain in South Dakota is less common than in the heart of summer, but showers and storms still show up sometimes. Precipitation averages 0.1 to 0.5 inches around the holiday, depending on where you are.
Thunderstorms can pop up, and some years bring strong winds or hail. The eastern side, like Sioux Falls and Aberdeen, tends to get more rain than the drier west.
Moisture swings from year to year. You might get a few dry years, then suddenly a wetter holiday with measurable rain. Since it’s unpredictable, it’s smart to plan for both dry and wet weather if you’ll be outside.
Weather Extremes on Record
South Dakota has seen some wild Labor Day weather. Record highs have hit the upper 90s to nearly 100°F (37–38°C). On the flip side, record lows have dropped into the 20s and 30s °F (-6 to 1°C) in some areas.
Once, Rapid City even got 1 inch of snow downtown during Labor Day. That was the earliest snow ever recorded for the holiday.
Other years, severe thunderstorms, heavy rain close to 1 inch in a day, or hot, dry spells have all happened. Early September weather in South Dakota can really keep you guessing.
Regional Weather Variations
Weather in South Dakota during early September changes a lot depending on location. Elevation, geography, and wind patterns all shape the temperatures and rainfall you’ll get.
Sioux Falls Climate on Labor Day
In Sioux Falls, highs usually reach the upper 70s and lows settle in the mid-50s around Labor Day. Records show temperatures swinging from the mid-30s up to over 100°F.
Rainfall stays pretty light, averaging 0.10 inches, but showers show up about 4 out of every 10 years. When storms roll through, they can dump heavy rain in a short burst.
Humidity feels moderate most of the time, and evenings cool down fast. If you’ll be outside after sunset, you might want a light jacket.
| Average | High | Low | Precipitation |
|---|---|---|---|
| Typical | 79°F | 55°F | 0.10 in |
Black Hills and Mount Rushmore Conditions
The Black Hills, including Mount Rushmore, sit higher than the eastern plains. You’ll find cooler daytime highs, usually in the low to mid-70s, and nights that drop into the upper 40s or low 50s.
Rain chances run a bit higher than in Sioux Falls, and afternoon showers or isolated storms can pop up. These storms don’t last long but can bring gusty winds.
Mornings feel crisp, and evenings get chilly because of the dry mountain air. If you’re heading to Mount Rushmore, bring layers—temperatures can swing quickly between sunny spots and shaded overlooks.
Missouri River Area Weather
Along the Missouri River, in towns like Pierre, you’ll notice warmer conditions than the Black Hills. Highs often hit the low to mid-80s, and lows stay in the mid-50s to low 60s.
The river valley holds warmth into the evening, so nights feel milder. Breezy afternoons happen a lot, especially in open areas near the water.
Rain isn’t rare, but it’s usually modest. Thunderstorms can form upstream and drift in, sometimes bringing heavy downpours for a short time. If you’re planning river activities, keep an eye out for fast-changing skies.
Daylight and Sunshine
In early September, South Dakota gets long days with plenty of usable daylight and a good shot at clear skies. Sunshine varies across the state, but it’s generally a nice time for outdoor plans.
Average Hours of Daylight
Around Labor Day, you’ll get about 12 hours and 30 minutes of daylight each day. Sunrise is close to 6:50 a.m., and sunset happens near 7:45 p.m., though exact times shift a bit depending on where you are.
Days are already getting shorter compared to midsummer, but you still have plenty of time for sightseeing, hiking, or road trips. Compared to July, you lose 2–3 hours of daylight, but it’s still way more than you’ll get in late fall.
In Rapid City, daylight averages about 12 hours 27 minutes in early September, and Sioux Falls is about the same. By mid-September, daylight drops to around 12 hours, so evenings start to show up a bit earlier.
Cloud Cover and Sunshine Probability
Chances for sunny skies run pretty high in early September. In Rapid City, about 70% of daylight hours are sunny. Sioux Falls and other eastern cities might see a bit more cloud cover, but clear days are still common.
You can expect 8 to 9 hours of real sunshine per day. That makes it easy to plan outdoor stuff without worrying about losing too much time to clouds.
Clouds tend to build more later in the month, but around Labor Day, skies usually stay clearer than in late summer. Mornings are often bright, with some afternoon clouds that can bring a quick shower.
If you’re coming for outdoor events or photography, your odds of getting good light are pretty solid this time of year.
Rainfall and Precipitation Trends
Rainfall around Labor Day in South Dakota is usually light, but it can swing from year to year. Sioux Falls and other cities often stay dry, though storms and heavier rain sometimes show up in early September.
Average Rainfall Amounts
In Sioux Falls, the average Labor Day precipitation is about 0.10 inches. That number comes from long-term climate records and shows that rain is usually minimal.
Across South Dakota, early September averages stay low. Most cities get less than half an inch of rain during this stretch. The holiday weekend is actually one of the drier times, especially compared to June or July.
Still, extremes happen. Sioux Falls once got 1.79 inches of rain on Labor Day in 1948, proving that localized storms can blow those averages out of the water. It’s rare, but it can happen.
Chance of Rain on Labor Day
The odds of measurable rain in Sioux Falls on Labor Day sit at about 40% based on records. So, you’re more likely to stay dry, but showers are definitely possible.
Across the state, the pattern’s similar. South Dakota’s Great Plains can switch up the weather fast—a sunny morning might turn into an afternoon thunderstorm.
Most rain events are short. All-day soakers don’t really happen much in early September. Instead, you’ll get a quick shower or a passing storm, especially in the eastern parts like Sioux Falls.
Humidity and Wind Conditions
In early September, you’ll usually find moderate humidity with just a few muggy spells. Steady winds often shape how comfortable the air feels. These patterns shift a bit between east and west, but most of South Dakota follows the same general trend.
Typical Humidity Levels
Humidity in South Dakota around Labor Day usually feels comfortable. In the east, in places like Sioux Falls and Aberdeen, dew points often run from the mid-50s to low 60s °F. The air doesn’t get too dry or sticky.
You might get a couple of muggy days, especially after summer storms. Sioux Falls averages about 2–3 muggy days in September, while Aberdeen gets 1–2 days. These don’t last long.
Western spots like Rapid City are even drier. Dew points there stay in the 40s and 50s °F, so the air feels crisp, and outdoor activities are more pleasant. Many travelers say the west is less humid than the eastern plains.
All in all, mild humidity shouldn’t mess with your plans for hiking or sightseeing. It’s still smart to carry water, but you won’t deal with the heavy, oppressive air you’d find farther south.
Prevailing Winds in Early September
Winds have a steady impact on how September weather feels. In Sioux Falls, average wind speeds hit about 10–11 mph. Aberdeen is about the same. Rapid City feels a bit calmer, closer to 8–9 mph.
Winds usually come from the northwest or south, depending on the weather system. A northwest wind brings drier, cooler air, while a southern breeze can make things warmer and a little more humid.
You’ll feel wind more directly out on the open plains in eastern South Dakota. The Black Hills near Rapid City block some of that, so breezes there are lighter and less predictable.
When you’re traveling, steady winds can make it feel colder than the temperature says. A light jacket in the morning or evening can make all the difference if you’ll be outside.
Travel and Outdoor Activity Considerations
Labor Day in South Dakota brings mild daytime temps and cooler nights, so it’s a solid time for outdoor trips. Just plan for changing weather—warm afternoons can turn chilly or stormy pretty quickly.
Best Outdoor Destinations
South Dakota offers a bunch of great outdoor spots in early September. The Black Hills have hiking trails where daytime highs usually land in the 60s and 70s, so you can actually enjoy those longer hikes without melting. Nights drop into the 40s, so yeah, you’ll want to toss a few layers in your bag if you’re camping out.
People love visiting Mount Rushmore around now since the crowds have thinned out compared to the chaos of midsummer. Afternoon temps feel just right, and you don’t have to fight that sticky humidity while you wander the memorial grounds.
In Sioux Falls, you might wander through Falls Park or hop on a bike and cruise the city’s trails. Highs hover close to 79°F, and evenings dip into the mid-50s, which makes it tempting to stay outside a little longer.
If you’re into scenic drives, the Peter Norbeck Scenic Byway in the Black Hills really shines this time of year. The weather stays mild, so you can take your time and soak up the views without sweating through your shirt.
Weather-Related Travel Tips
Expect some wild temperature swings out here. Daytime highs usually hang out in the 70s, but once the sun goes down, it can drop into the 40s—especially up in the higher parts of the Black Hills. Even if the day feels toasty, you’ll probably want a light jacket or sweater handy.
Bring rain gear, just in case. Those quick thunderstorms like to pop up in the afternoon and sweep across the plains before you know it.
If you’re camping or hiking, keep an eye out for the first hints of frost. Some spots get their first freeze in the Black Hills by late September, so those chilly mornings can catch you off guard.
Heading into Sioux Falls or another city? Layer up. That way, you can handle the warm afternoons and those surprisingly crisp evenings without missing a beat.