Honestly, if you’ve lived in the 19720 area for more than a week, you know the drill. You walk out the door in a heavy parka and by noon you’re wondering why you didn't just wear a hoodie. The weather for New Castle DE 19720 is basically a masterclass in indecision.
Right now, as of mid-January 2026, we’re sitting in that weird "in-between" space. Today specifically—Saturday the 17th—is a perfect example. It's roughly 33°F outside, but with that 9 mph southwest wind, it actually feels more like 26°F. It’s the kind of cold that sneaks under your collar. We’ve got light rain falling, and the humidity is a heavy 88%.
The Mid-January Slump
You'd think by now we’d be buried in a foot of snow, but the data tells a different story. While the day started with light rain, the forecast for the rest of today is calling for a transition into light snow. The high is expected to hit 39°F, which is just high enough to turn everything into a slushy mess rather than a winter wonderland. Tonight, it’ll drop back toward 32°F with a mix of rain and snow.
People always ask if Delaware winters are getting milder. Well, looking at the stats from the Delaware Climate Office, the mean annual temperature in New Castle County has historically hovered around 54°F, but there’s been a noticeable creep upward since the 80s. January is officially our cloudiest month, with the sky being overcast about 52% of the time.
It's gloomy. No way around it.
Why 19720 Weather is Actually a Science Experiment
Living near the Delaware River changes the game. We're in this transition zone between humid subtropical vibes from the south and that humid continental chill from the north. The water actually acts like a giant radiator, keeping us from hitting those crazy temperature extremes you see further inland.
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But don't let that fool you.
When a Nor’easter rolls up the coast, New Castle takes it right on the chin. We’ve seen it before with storms like Hurricane Irene or the big January blizzards where the storm surge at Reedy Island hits over 8 feet.
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What to Expect for the Rest of Winter 2026
So, what’s the deal for the next few months?
- Temperature Trends: The NOAA Climate Prediction Center is leaning toward a continuation of the "winter chill" through late January.
- Precipitation: It’s a toss-up. We’ve had five straight months of below-normal rain leading into 2026. We’re basically in a "dry" spell, even if the puddles outside say otherwise.
- The "La Niña" Factor: There’s a weak La Niña hanging around, which usually means more frequent but smaller snow events for us rather than one giant "Snowmageddon."
The ground is surprisingly dry underneath. Even with the light rain today, the year-to-date rainfall for the 19720 zip code is actually way below average. Farmers and gardeners around here are probably looking at those soil moisture levels with a bit of a side-eye.
Practical Survival for New Castle Residents
If you're heading out toward the New Castle Airport or just running errands down Route 13, keep the ice scraper handy. Tomorrow (Sunday) has a 50% chance of snow showers with maybe an inch of accumulation. It's not a lot, but on our roads, an inch is plenty to cause a headache.
By Monday—Martin Luther King Jr. Day—the sun finally decides to show up. It’ll be around 35°F, but clear. Then things get real. Tuesday and Wednesday are looking clear but significantly colder, with overnight lows dipping into the low teens.
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Actionable Next Steps:
- Check your tire pressure: These 30-degree swings (from 39°F today to 10°F by Tuesday night) will make your "low pressure" light pop on.
- Salt the walkways tonight: Since we're expecting that rain-to-snow transition at 32°F, the "freeze-thaw" cycle is going to turn sidewalks into ice rinks by Sunday morning.
- Monitor the water table: If you rely on a well in southern New Castle County, keep an eye on local drought reports; the late 2025 dry spell hasn't fully recovered yet despite the winter dampness.