Honestly, if you’re looking at a map of South Dakota, Lennox looks like a quiet little spot just south of Sioux Falls. But the weather in Lennox SD? That’s a whole different story. It’s the kind of place where you can wake up to a serene, frost-covered lawn and end the day wondering if your roof is going to stay attached.
The wind here doesn't just "blow." It hunts. Specifically, that northwest wind that cuts across the prairie like a serrated knife.
The Reality of a Lennox Winter
Right now, as of mid-January 2026, we’re sitting in the thick of it. If you stepped outside today, Saturday, January 17, you’d find a high of just 12°F. That sounds cold, sure, but it’s the -17°F wind chill that actually dictates your life. You don't just "go for a walk" in that. You survive the dash from the front door to the car.
The humidity is sitting around 64% today, which in the summer feels like a warm hug, but in January, it just makes the cold feel "heavy." It clings to your coat. We’ve got a 10% chance of snow during the day, jumping to 25% tonight. It’s light, powdery stuff—the kind that the 19 mph northwest winds love to whip into drifts tall enough to swallow a mailbox.
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Tomorrow isn't looking much friendlier. We’re expecting snow showers with a high of 24°F, but the wind is amping up to 24 mph. By Monday and Tuesday, we're looking at more light snow and highs that struggle to break the low 20s.
Summer is a Different Beast Entirely
If you hate the cold, just wait. Lennox flips the script fast. By the time July rolls around, those freezing northwest gusts are replaced by heavy, humid air pushing up from the Gulf.
- The Hottest Month: July takes the crown. We’re talking average highs of 85°F, but it's the "feels like" temp that gets you.
- The Storm Window: May and June are the wettest months. June alone can dump over 4 inches of rain.
- The Clear Skies: If you want to see the stars, July is your best bet, with clear or partly cloudy skies about 73% of the time.
Most people who aren't from around here think South Dakota is just one big flat freezer. It’s not. It’s a humid continental climate, which basically means we get the extremes of everything. We get the "Dfa" climate classification—hot summers, freezing winters, and very little "chill" in between.
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What the Averages Don't Tell You
You can look at a chart and see that the average high in January is 28°F, but averages are liars. One week you’re at 45°F and the snow is melting into a muddy mess, and the next, a polar vortex drops the mercury to -10°F.
Severe weather is a legitimate part of the lifestyle here. Between 1980 and 2024, South Dakota saw dozens of billion-dollar weather disasters. In Lennox, that usually translates to severe thunderstorms in the late afternoon—typically between 4 PM and midnight—that bring hail the size of quarters and, occasionally, the threat of a tornado.
The wind is the constant. It averages around 10 mph in the winter and barely drops to 9 mph in the summer. It’s always there, whispering or screaming across the fields.
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Living With the Forecast
If you're moving here or just passing through, you have to respect the weather in Lennox SD. It’s not like the coast where things are predictable.
- Keep a "Winter Kit" in the trunk: I’m talking blankets, a real shovel (not a plastic toy), and some sand or kitty litter. If you slide into a ditch on a gravel road outside of town, you might be waiting a bit.
- Seal your north-facing windows: That northwest wind is relentless. If you have a draft, you’ll feel it in your heating bill by December.
- Watch the sky in June: When the clouds start looking like bruised knuckles, get the car in the garage. Hail is a frequent, expensive visitor.
- Embrace the "Shoulder" Months: September is, quite frankly, the only time the weather is actually polite. The highs are in the 70s, the bugs are dying off, and the humidity finally takes a break.
The weather here is a test of character. It’s why people in Lennox are so hardy. You have to be when the sky is trying to freeze you one month and melt you the next.
Check your tire pressure before the Monday morning commute. The temp is dropping to -2°F Sunday night, and your "low tire" light is almost guaranteed to be the first thing you see when you start the engine.