You know that feeling when you walk out the door in South Jersey and the air just hits you differently? One day it's a crisp, apple-picking breeze, and the next, it feels like you're breathing through a warm, wet washcloth. That’s the weather in Cinnaminson New Jersey for you. It’s a bit of a moving target.
Cinnaminson sits in a sweet spot—or a tough spot, depending on how much you hate shoveling snow—right in the Delaware Valley. Because we're nestled between the river and the Atlantic, we get a mix of everything. It’s technically a humid subtropical climate, but honestly, it feels more like a four-act play where the actors sometimes forget their lines and show up in the wrong season.
The Reality of Our Four Seasons
Winter here isn't messing around this year. We’ve seen January 2026 start with some pretty bitter stretches. Typically, you’re looking at highs around 39°F and lows that dip into the mid-20s. But it’s the wind off the river that really gets you. It makes that 30-degree morning feel like 15. Snow is a bit of a wildcard; some years we get a dusting that disappears by noon, and others, like back in the late December/early January stretches we just hit, we get enough to keep the kids out of school for a bit.
Spring is a total mood swing.
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By April, things start to feel human again. You’ll get those gorgeous 63°F days where everyone is at Wood Park, but keep your jacket close. The nights still drop to near freezing. It’s also our wettest time. May usually takes the crown for the most rain, with about a 37% chance of a downpour on any given day. If you’re planting a garden near Riverton Road, wait until after the first week of May. Seriously. The late frost is a silent killer for tomatoes.
Summer Heat and the Humidity Factor
July is a beast. There’s no other way to put it.
The average high is 87°F, but that number is a bit of a lie because it doesn't account for the humidity. We regularly hit 90% humidity, making the air feel thick and "sticky." It’s the kind of weather where you move from one air-conditioned building to another and call it a day. We’ve also seen an uptick in "hot days"—those spikes above 94°F—which used to be rare but are becoming a regular part of the July and August rotation.
- Hottest Month: July (Highs of 87°F)
- Coldest Month: January (Lows of 23°F)
- Wettest Month: May
- Clearest Month: September
Is It Always Cloudy?
Not really, though December might make you feel otherwise. December is officially our gloomiest month, with the least amount of sunshine. If you're looking for those perfect "blue sky" days, September and October are your best bets. October actually averages about 14 hours of clear or partly cloudy skies a day. It’s easily the best time to be outside in Cinnaminson. The humidity drops, the bugs clear out, and the sun actually stays out long enough to enjoy it.
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Flood Risks and Extreme Shifts
We have to talk about the water. Since we’re right on the Delaware, flooding is a real conversation here. While Cinnaminson isn't as vulnerable as the Jersey Shore, the "Coastal Vulnerability Index" for parts of the township near the creek and river is something local officials watch closely.
Heavy rain events are getting more intense. Historically, we’d get about 45 inches of rain a year. Projections for the coming decades show that creeping up toward 50 inches, often delivered in massive 48-hour bursts. If you live in one of the lower-lying spots near the Pompeston Creek, you've probably noticed the "minimal flood risk" label on FEMA maps doesn't always match what happens during a heavy Nor'easter.
What to Actually Pack (or Wear)
If you're visiting or just moved here, forget a "one-season" wardrobe. You need layers.
- Winter: A heavy parka and waterproof boots. The slush on Route 130 is legendary and gross.
- Spring: A windbreaker and an umbrella you actually trust. Cheap umbrellas don't survive March winds here.
- Summer: Light, breathable fabrics. Linen is your friend.
- Fall: A light fleece or denim jacket.
Honestly, the weather in Cinnaminson New Jersey is mostly predictable if you pay attention to the humidity levels rather than just the temperature. The "feels like" temp is the only one that matters from June through August.
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If you're planning an outdoor event, aim for the last two weeks of September. You'll miss the summer swelter and beat the November chill. Just keep an eye on the tropical storm remnants that occasionally wander up the coast—they like to dump a month's worth of rain on us in about six hours.
Actionable Insights for Cinnaminson Residents:
- Winterize early: Ensure your outdoor pipes are insulated by late November, as December 2025 proved that deep freezes can arrive ahead of schedule.
- Check your drainage: Given the 2026 trends of concentrated heavy rainfall, clear your gutters and check your sump pump every March before the May rains hit.
- Planting guide: Stick to the "Mother's Day Rule" for sensitive plants to avoid the erratic late-April frost common in the Delaware Valley.
- Energy efficiency: With rising summer "heat risk" days, consider attic insulation or solar film for south-facing windows to combat the July humidity spikes.