If you’ve spent any time in Union County, you know the deal. One day you’re wearing a light hoodie at Oak Ridge Park, and the next, you’re digging your car out of a foot of snow. It’s wild. The weather in Clark New Jersey is basically a masterclass in variety. It’s humid, it’s freezing, it’s gorgeous, and it’s occasionally a little bit scary.
Honestly, Clark doesn’t do things halfway.
Because we’re tucked into that specific slice of North-Central Jersey, we get hit with a mix of continental air from the west and maritime influence from the Atlantic. It creates a climate that feels very "four seasons," but those seasons often overlap or skip a beat entirely.
Why the weather in Clark New Jersey is so moody
Basically, Clark sits in a humid subtropical zone, but it flirts with a humid continental climate.
What does that mean for your weekend plans?
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It means July is going to feel like a steam room. It means January is going to make you regret every decision that led you to leave your house. The average temperature usually hangs between 26°F and 87°F. Sure, you’ll get those random spikes where it hits 95°F in August and everyone crowds the AC at the Clark Commons, but those aren't the daily norm.
Low temperatures rarely dip below 12°F, though when the wind whips across the flat parts of the township, it certainly feels colder.
The Summer Sizzle and the "Humid" Factor
Summer in Clark is... a lot.
From late May to mid-September, the heat is heavy. We’re talking about an average daily high above 78°F. July takes the crown as the hottest month. You’re looking at highs of 87°F and lows that stay around 68°F. But the temperature only tells half the story.
The humidity is the real protagonist here.
Because Clark isn't right on the coast—we’re a bit inland from the Arthur Kill and the Raritan Bay—we don't always get that refreshing sea breeze that hits places like Belmar or Asbury Park. Instead, the moisture just sits there. It’s that "thick" air where you step outside and immediately feel like you need a second shower.
Is it all bad? No.
The evenings can be incredible. If you’re at a high school football game or just sitting in your backyard, that transition from a sweltering 85°F afternoon to a breezy 70°F night is why people stay here.
Surviving the Clark Winter
Winter is a different beast.
It kicks off in early December and doesn't really let go until mid-March. January is the peak of the "why do I live here?" season. Highs struggle to reach 41°F, and the nights regularly drop to 27°F.
Snow is a guarantee, but the amount is the big mystery.
Some years, we get a few dustings. Other years, like during those historic Nor'easters, Clark gets absolutely hammered. The town’s public works department usually stays on top of the salting, but if you’re commuting down the Garden State Parkway during a Clark snowstorm, you already know the stress.
Ice is actually the bigger villain. Because our temperatures hover so close to the freezing mark (32°F), we get a lot of that "rain-to-snow" transition that turns driveways into skating rinks.
Rainfall and the "Wet" Seasons
Rain is pretty evenly spread out, which keeps the township looking green.
We get about 50 inches of precipitation a year. That’s actually higher than the national average. It’s not just the spring showers, either. Late summer thunderstorms are a staple of life in Clark. You’ve probably seen those dark clouds rolling in over the Westfield border around 4:00 PM on a Tuesday. They hit hard, they dump a few inches of rain, and they’re gone in an hour.
Extreme Events: Flooding and More
We have to talk about the water.
Clark has a history with flooding, especially in low-lying areas near the Robinson’s Branch of the Rahway River. When massive systems like Hurricane Ida or Superstorm Sandy come through, the local infrastructure gets tested.
If you’re looking at property in Clark, the weather history matters.
The township has worked on mitigation, but nature usually has the final say. Significant storms have historically caused issues near the reservoirs and local streams. It’s something residents just keep in the back of their minds whenever the forecast mentions "tropical remnants."
When is it actually nice out?
If you’re looking for the sweet spot, aim for September.
September is arguably the best month for the weather in Clark New Jersey. The humidity finally breaks. The sky is clear or "partly cloudy" about 63% of the time. Temperatures are a comfortable 70°F to 78°F. It’s perfection.
The "clearer" part of the year starts in late June and lasts until mid-November.
Spring is great too, particularly May, but it’s unpredictable. One week you have blooming azaleas and 75°F weather; the next week, it’s a cold, grey drizzle that lasts for four days straight.
Actionable Tips for Residents and Visitors
- Check the Dew Point, Not Just the Temp: In July, an 85°F day with a low dew point is great. If the dew point is over 70, stay inside.
- Garden Prep: Wait until after Mother's Day to plant anything sensitive. Clark is notorious for that one last frost in late April that kills everyone's tomatoes.
- Commuter Strategy: If you take the GSP or Route 1/9, keep a winter kit in your trunk. A 20-minute drive can turn into a 3-hour crawl during a sudden Clark snow squall.
- Flood Insurance: If you’re near the Rahway River basin, just get it. Even if you haven't seen water in years, the shifting climate patterns in New Jersey mean "100-year floods" are happening way more often.
- Leaf Season: November is beautiful but windy. If you have big oaks or maples, the wind off the open spaces in Clark will dump every leaf in the county into your yard. Prepare your blower.
The weather here is a lot of things, but it’s never boring. You just learn to keep a coat and a pair of flip-flops in your car at all times. It’s just the Jersey way.
Next Steps for Staying Safe
To stay ahead of the volatile shifts in Clark, make sure you're signed up for the Union County FirstAlert system. This provides localized emergency weather notifications that are often more specific than the generic "New York City Area" forecasts you get on national apps. Additionally, check the township’s official social media pages during storm events for real-time updates on road closures near the Rahway River crossing and the Parkway entrances. Keeping an eye on the Rutgers NJ Weather Network station data for the Rahway/Clark area will give you the most accurate local wind and precipitation counts.