If you’re checking the weather in Lebanon NH because you’re planning a weekend trip or—heaven help you—you’re thinking of moving here, you need more than just a 10-day forecast. Most people look at the numbers and think, "Okay, typical New England."
They are wrong.
Lebanon is a weird little pocket of the Upper Valley. It’s a place where the Connecticut River acts like a giant temperature regulator and the hills of the Mascoma Lake area decide they want to have their own private snowstorm while the downtown is perfectly clear. Honestly, it’s a bit of a localized atmospheric circus.
The Cold Hard Truth About Lebanon Winters
Everyone knows New Hampshire is cold. But Lebanon’s winter is a specific brand of "stinging."
January is basically the boss level. You’re looking at average highs of about 30°F, but the lows drop to 9°F or even lower. We aren't just talking about a crisp breeze; we're talking about that dry, Canadian air that makes your nostrils stick together the second you walk out of Lucky's Coffee Garage.
The snowfall averages about 68 to 76 inches a year. That sounds manageable until you realize the "continuous coverage" lasts nearly 100 days. Basically, the ground disappears around Thanksgiving and doesn't show its face again until April.
Why the "Valley Fog" is a Real Thing
Because Lebanon sits in the valley, we get this wonderful phenomenon called an inversion.
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Cold air gets trapped under a layer of warm air. The result? Thick, pea-soup fog that clings to the Lebanon Municipal Airport (KLEB) and makes your morning commute feel like a scene from a horror movie. It’s beautiful, sure, but it also keeps things damp and chilly even when the sun is trying to do its job.
Summers Aren't Just Mild—They’re Muggy
There’s this myth that northern New England is always cool.
Tell that to someone standing on the Lebanon Green in July.
While the average high is a pleasant 81°F, we’ve seen record highs hit 100°F as recently as June 2025. It’s a "humid continental" climate, which is just a fancy way of saying it gets sticky. The moisture from the river and the surrounding forests creates a humidity that can make an 85-degree day feel like 95.
Fortunately, the nights usually cool down into the 50s. You’ll still want an AC unit for those three weeks in July, but you can usually get by with a box window fan and some optimism the rest of the time.
The Rain, The Ticks, and The "Mud Season"
We have to talk about the fifth season. It’s not spring. It’s Mud Season.
Between March and May, Lebanon gets a messy mix of melting snow and about 3-4 inches of monthly rain. This is when the dirt roads in the outskirts of town become essentially impassable for anything smaller than a Subaru with high clearance.
- The Pollen Explosion: May is beautiful, but the pollen count in the valley is brutal. If you have allergies, the weather in Lebanon NH during late spring will be your nemesis.
- Tick Watch: Because our winters are getting slightly shorter, the black-legged tick population is booming. Warm, wet springs are their favorite.
- Flash Floods: We saw record rain in 2023 (over 21 inches in three months!), and those localized deluges are becoming more common.
What Really Matters: The Lifestyle Shift
You don't just "watch" the weather here. You live it.
The lifestyle in Lebanon is dictated by the sky. When it’s 20°F and sunny in February, the rail trail is packed with cross-country skiers. When it’s 75°F in September, everyone is at the farmers market.
Expert Tip: Don't trust the "feels like" temperature on your phone. If you are in the shadows of the hills, it's 5 degrees colder. If you're on the asphalt near West Leb's shopping plazas, it's 7 degrees hotter. The "Heat Island" effect is real, even in a small city like ours.
Real Talk on Gear
If you’re moving here, forget the fashion coat. You need:
- A "Puffy": A high-fill down jacket.
- Muck Boots: Essential for the March/April slush.
- Snow Tires: All-seasons are a lie when you're trying to climb a 12% grade hill in a January squall.
Actionable Insights for Navigating Lebanon’s Climate
If you want to survive and thrive with the weather in Lebanon NH, follow these steps:
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- Bookmark the KLEB Station: The Lebanon Municipal Airport station is the most accurate for the city center. Apps that use generic "Upper Valley" data often miss the valley-specific shifts.
- Winterize by October: Do not wait for the first flake. Get your snow tires on by Halloween. The local shops get backed up for weeks once the first dusting hits.
- Invest in a Dehumidifier: Basements in the valley get incredibly damp during the humid July-August stretch. You'll save yourself a lot of mold-related headaches.
- Plan Outdoor Work for the Morning: In the summer, the humidity peaks in the late afternoon. If you’re hiking Boston Lot or gardening, do it before 10:00 AM.
- Layers are a Religion: It’s not uncommon to start the day at 35°F and end it at 65°F in October. A base layer, a fleece, and a shell are your best friends.
The weather here is temperamental, sometimes frustrating, but never boring. Just remember: there’s no such thing as bad weather, only bad clothing choices.