If you’ve spent any real time in Hammonton, you know it’s not just the blueberries that are unique. The town sits in this strange pocket of South Jersey where the weather feels like it’s playing by its own set of rules. One minute you're enjoying a crisp, sunny morning at a farm stand, and the next, a humidity wall hits you like a wet blanket.
Honestly, the weather for Hammonton NJ is a bit of a local obsession, and for good reason. Between the sandy soil of the Pine Barrens and the town's proximity to the Atlantic, we get a microclimate that can be wildly different from what they’re seeing up in Cherry Hill or down in Cape May.
The Current Chill and What’s Coming Next
Right now, we’re in the thick of January, which is historically Hammonton’s coldest month. If you stepped outside this morning, January 13, 2026, you probably felt that 31°F bite in the air. It’s clear, but those periodic clouds are keeping things gray.
We’re looking at a high of about 49°F today. That’s actually a bit of a "heat wave" considering the average January high is usually closer to 41°F. But don't get too comfortable. By Thursday, the mercury is expected to crash back down to a high of 35°F, with overnight lows dipping into the low 20s.
If you’re planning a trip to the Bagliani’s or heading out for a walk at Batsto, keep an eye on Wednesday night. There's a 35% chance of some light snow mixing in with rain. It won't be a blizzard, but in Hammonton, even a dusting on the backroads can make things slick fast.
Why Summer in Hammonton is a Different Beast
Most people think "Jersey Shore weather" when they think of South Jersey summers. Hammonton doesn't get that luxury. Since we’re tucked inland, we don't get the consistent sea breeze that keeps places like Ventnor or Margate bearable in July.
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Instead, we get the heat trapped by the pines.
July is typically our hottest and wettest month. Average highs sit around 86°F, but it’s the humidity that really gets you. It’s common to see 90-degree days where the air feels thick enough to chew. This is also when we see those sudden, violent afternoon thunderstorms. According to data from the New Jersey Weather and Climate Network, July usually brings nearly 5 inches of rain, often delivered in massive downpours that can flood Route 54 in a heartbeat.
The "Blueberry Frost" Anxiety
If you want to see a Hammonton local truly stressed, check the forecast in late April.
Our farmers live and die by the "last frost" date. Typically, that happens between May 1st and May 10th. However, if we get a rogue frost in late April—like we’ve seen in recent years—it can be devastating for the blueberry crop. When the Duke or Bluecrop varieties are in bloom, even a few hours of 28°F temperatures can wipe out 15% of a harvest overnight.
You’ll see growers out there in the middle of the night, using giant fans or irrigation systems to keep the blossoms from freezing. It’s a high-stakes game of chicken with Mother Nature.
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The Pine Barrens Effect
Have you ever noticed that it feels colder in Hammonton than it does in Philadelphia, even though they’re only 30 miles apart? That’s the "Radiational Cooling" effect of the Pine Barrens.
The sandy soil in our area doesn't hold heat well. On clear, calm nights, the heat escapes into the atmosphere rapidly. This leads to massive temperature swings. It’s not rare to have a 70°F afternoon followed by a 35°F night.
- Sandy Soil: Acts like a desert, losing heat fast.
- Tree Cover: The dense pines can trap moisture, leading to that "suffocating" humidity in August.
- Wind: We’re surprisingly windy in March, with averages hitting 17 mph.
Notable Weather Weirdness in Hammonton History
We’ve had some doozies over the years. While we usually escape the worst of the hurricanes that hit the coast, the remnants can be brutal.
Back in 1939, a tropical storm caused major flooding in the Pine Barrens, even derailing a train in nearby Chatsworth. More recently, the drought of late 2024 and early 2025 had everyone on edge. We went nearly 40 days without a drop of rain, which is unheard of for this part of the state. It got so dry that the state had to issue a Drought Warning in December 2025.
Thankfully, the rain we’ve had so far this January is starting to bridge that gap, though we’re still technically "abnormally dry" according to the latest USDA Drought Monitor reports.
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What Most People Get Wrong About Hammonton Weather
A big misconception is that if it’s snowing in Philly, it’s snowing in Hammonton.
Actually, we are often on the "rain-snow line." Because we’re closer to the ocean, that slightly warmer salt air often turns what would be 6 inches of snow into a slushy, freezing rain mess. It’s why our seasonal snowfall average is only about 18 inches—significantly less than what you’d find in North Jersey.
Living With the Forecast: Practical Tips
If you're living here or just visiting, you need a strategy. The weather for Hammonton NJ isn't something you can just ignore.
First, download a hyper-local weather app or bookmark the NJ Mesonet station for Hammonton (located at Mill Rock Farm). General apps usually pull data from Atlantic City International Airport (KACY), which is about 15 miles away and often 5 degrees cooler or warmer than downtown Hammonton.
Second, if you’re gardening, don't trust a warm April. Wait until after Mother’s Day to put your sensitive plants in the ground. The "Pine Barrens Chill" has claimed many a tomato plant on a clear May night.
Lastly, keep a "car kit" for the summer. Those afternoon storms move fast. Having an umbrella and a change of shoes isn't just a suggestion; it's a necessity when a July deluge turns the parking lots into ponds.
Moving forward, keep a close watch on the Wednesday night transition. If that rain turns to snow earlier than expected, the morning commute on the Atlantic City Expressway will be a nightmare. Check the local Mesonet sensors before you head out to see the actual ground temperature, as it often lags behind the air temp.