Planning a trip to New Hampshire around Labor Day? You’ll want to be ready for weather that swings between late-summer warmth and those first little hints of fall.
Most years, daytime highs land in the low 70s, while nights cool off into the 50s. That’s pretty ideal for both hiking and evening events, if you ask me.
This blend of mild afternoons and crisp evenings makes the holiday weekend a favorite for exploring the state.
Rain can show up, but it rarely ruins the whole weekend. Early September usually brings partly sunny days with the occasional shower, so tossing a light jacket and umbrella in your bag is just smart.
The skies tend to be clearer than in midsummer, so you have a good shot at those classic scenic views without the muggy haze.
These weather patterns let you enjoy everything from hiking in the White Mountains to coastal walks in Portsmouth.
Labor Day weather often feels more predictable and comfortable than the stormier midsummer stretches or the chilly, damp days later in fall.
Labor Day Weather Overview in New Hampshire
In early September, mild days and cool nights cover most of New Hampshire.
Temperatures shift with elevation and region, while rain chances stay moderate and the sky offers a mix of sun and clouds.
These patterns really shape how easy it is to get outside during the long weekend.
Typical Temperature Ranges
Daytime highs in southern New Hampshire usually climb into the mid-70s°F to low 80s°F (24–28°C).
Up north in the White Mountains, highs stick closer to the upper 60s°F to mid-70s°F (20–24°C).
Nights get noticeably cooler, often dropping into the 50s°F (10–15°C). If you’re in higher elevations, you might even see temps dip into the 40s°F (4–9°C).
Packing layers makes sense. Light clothes are great for the day, but you’ll want a jacket or sweater once the sun goes down.
Those cool nights really signal the start of fall, especially up north.
Humidity usually drops compared to midsummer, so even if the highs hit the 80s, the air feels pretty comfortable.
Precipitation Patterns
New Hampshire has a humid continental climate, so you can’t rule out rain in early September.
On average, the month brings 3–4 inches of rain, with showers that are usually short but sometimes heavy.
Quick-moving thunderstorms sometimes pop up in the afternoons. They don’t tend to last long, but they can dump a lot of rain in a hurry.
Southern and central New Hampshire see these storms a bit more often than the northern mountains.
Rain usually comes in bursts, not all-day downpours. You’ll probably still get plenty of dry hours for hiking, boating, or whatever else you’ve got planned.
A light rain jacket or umbrella definitely comes in handy.
Sunshine and Cloud Cover
You’ll see a mix of sunshine and partial cloud cover across most of New Hampshire for Labor Day weekend.
Early September averages about 55–60% possible sunshine, so more than half the daylight hours bring at least some sun.
Mornings often start out clear, then clouds build up in the afternoon. That’s just how the weather works here, with Atlantic moisture and inland air mixing things up.
Mountain spots like Mount Washington get more clouds, while the Seacoast and southern valleys usually see longer sunny stretches.
Where you are in the state can make a big difference in what the sky looks like.
Temperature Trends for Early September
Early September brings mild afternoons and cool nights as summer fades toward fall.
You’ll get daytime warmth that’s perfect for being outside, but you’ll want a light jacket in the evenings.
Average Highs and Lows
During the first week of September, average highs across New Hampshire run from the upper 60s °F to mid-70s °F (about 20–24 °C).
That’s warm enough for hiking, fairs, or time by the lake, without the sticky heat of midsummer.
Average lows usually land between the mid-40s °F and low 50s °F (7–12 °C). Nights can feel surprisingly crisp, especially away from the coast, so layers are your friend.
In Manchester and Nashua, highs reach the low to mid-70s °F, with lows sticking to the low 50s °F.
Up north in Berlin or Bethlehem, it’s cooler—highs in the upper 60s °F and lows dipping into the mid-40s °F.
This swing between day and night temps really lets you know fall’s on the way.
If you’re camping or planning to be outside after dark, bring something warm.
Regional Differences Across the State
New Hampshire’s landscape creates some real temperature differences.
In the south—places like Concord or Portsmouth—you’ll see highs around 72–75 °F (22–24 °C) and lows near 50–52 °F (10–11 °C). That’s a bit milder than up north.
In northern New Hampshire, including areas near the White Mountains, highs hover around 68–72 °F (20–22 °C). Lows often fall into the low to mid-40s °F (6–7 °C), which can feel chilly by sunrise.
At higher spots like Mount Washington, it’s much cooler. Early September highs average only in the upper 40s °F (9–10 °C), with lows in the 30s °F (1–3 °C).
You could see a 20–25 °F difference between southern valleys and mountain peaks on the same day.
Packing for both warm afternoons and brisk nights makes sense, especially if you’re traveling around the state.
Rainfall and Precipitation Chances
Rain around Labor Day in New Hampshire usually stays limited, with many years seeing just light or scattered showers.
The state averages steady precipitation throughout the year, but early September often leans drier. Still, brief systems can bring a quick shower or an isolated storm.
Likelihood of Rain on Labor Day
Labor Day itself usually stays mostly dry across New Hampshire.
Average rainfall for early September is modest—totals often come in under 3–4 inches for the whole month, spread out over several days.
So, the odds of steady rain on the holiday are pretty low.
Daytime highs in the 70s or low 80s, paired with comfortable humidity, make outdoor plans easy.
Coastal areas can be a bit cooler thanks to sea breezes, but they’re also likely to stay dry.
Rain chances bump up only a little if a weak front rolls through. Even then, showers tend to be brief and light, not the kind that wipe out your whole day.
If you’re hosting something outside, you’ll mostly just need to watch for a passing cloud or a quick sprinkle.
Thunder Showers and Storm Systems
You should keep an eye out for isolated thunder showers, especially in the north and at higher elevations.
These usually form in the afternoon when the sun heats up the landscape. They don’t last long, but they can bring a quick burst of rain.
Sometimes, an upper level system or a passing cold front slides through. That can bring scattered showers or a thunderstorm, but widespread heavy rain is rare.
When a front passes, rainfall amounts vary a lot. One town might get less than a tenth of an inch, while another could see close to an inch.
This patchy pattern means it’s smart to check local forecasts if you’re moving around the state.
Sunshine and Cloud Patterns
Around Labor Day, New Hampshire skies bounce between clear and cloudy.
You’ll see a mix of bright sun, scattered clouds, and sometimes a bit of overcast as summer gives way to fall.
These swings affect both how much light you get and how long daylight lasts.
Partial Sunshine and Cloudy Intervals
Early September usually brings 18 days with some sun, counting both fully sunny and partly sunny days.
On average, about 9 days are mostly clear and another 9 days bring partial sunshine, with clouds covering 40–70% of the sky.
So, even on cloudier days, you’ll likely get a few hours of sun for your plans.
Afternoon skies can shift fast, with sunbreaks and cloud cover trading places.
Compared to midsummer, the sky is a bit more unpredictable, but you still get plenty of bright days.
Overcast periods don’t stick around long and aren’t as common as in late fall or winter.
If you’re hiking, boating, or heading to the coast, expect to move between sun and shade all day. That’s actually pretty comfortable—not as harsh as July sun.
Daylight Hours and Seasonal Changes
By early September, daylight keeps shrinking after the summer peak.
You get about 12 hours and 40 minutes of daylight each day, with sunrise near 6:15 a.m. and sunset close to 7:30 p.m.
Possible sunshine averages 56%, so you see the sun a bit more than half the time between sunrise and sunset.
That’s more than late autumn, but less than midsummer.
You’ll notice the days getting shorter, especially in the evenings. Each day loses about 2–3 minutes of light, so sunset creeps earlier as September moves on.
If you’re traveling, it’s smart to plan outdoor stuff earlier in the day.
Evening light is still long enough for late dinners or walks, but twilight comes quicker than in July or August.
Weather Impacts on Outdoor Activities
Labor Day in New Hampshire usually brings mild temps in the 70s, low humidity, and not much rain.
That makes it easy to spend hours outside, though dry spells can raise fire risks and affect some activities.
Best Times for Outdoor Events
You’ll usually see comfortable highs in the mid to upper 70s, with some inland spots touching 80°F.
Nights cool into the 50s, so camping and evening events feel nice—not too hot, not too cold.
Rain chances stay low. When showers do pop up, they’re often brief and scattered.
Most outdoor gatherings—cookouts, parades, lake trips—can go on without much worry about the weather.
If you’re planning a sports event or festival, the cooler air compared to midsummer means less heat stress.
Coastal areas might be a few degrees cooler with sea breezes, while the northern mountains could see a little more cloud or a quick shower.
Quick guide for event planning:
- Daytime: 75–80°F, low humidity
- Evening: 50–55°F, great for campfires
- Rain risk: Low, mostly light showers if anything
Fire Danger and Drought Concerns
Late summer often brings dry spells, and New Hampshire sometimes gets below-average rain heading into September.
Even on clear, beautiful days, the lack of steady rain can bump up fire danger in forests and fields.
If you’re hiking, camping, or planning a bonfire, check local fire warnings first.
Sparks from grills or campfires can spread fast when things are dry. Many towns may put restrictions on open flames, especially if it’s been dry for a while.
Dry weather also lowers stream and lake levels, which can limit boating or fishing in some spots.
It doesn’t stop the fun, but you’ll need to pay extra attention to safety and local advisories.
Keeping up with fresh forecasts helps you enjoy the outdoors while staying safe during ongoing drought conditions.
Comparing Labor Day Weather to Other Months
Early September temperatures usually fall between the heat of midsummer and the chillier days of fall.
Rainfall and daylight shift too, so you get a nice mix of late-summer comfort and those first signs of autumn.
How September Differs from Summer
By Labor Day, you can usually feel a drop from the peak summer heat. In southern New Hampshire, average highs in July hit about 28°C (82°F).
Early September feels quite a bit cooler, with averages closer to 22°C (72°F). Up north in Berlin, things cool down even faster, with highs around 19°C (66°F).
Humidity finally backs off compared to July and August. In coastal Portsmouth, muggy days in midsummer show up about 7–9 days per month.
By September, you only get 2–3 muggy days, which is a relief if you ask me. Outdoor plans just feel easier without that heavy, sticky air hanging around.
Rainfall patterns shift a bit too. June through August usually bring 70–95 mm of monthly rain.
September totals are pretty similar, but the rain spreads out over fewer stormy days. Thunderstorms still pop up, but you notice them less as the season changes.
Daylight stands out as another big difference. In July, you get about 15 hours of daylight.
By September, it’s closer to 12 hours. That shorter window definitely changes how you plan things, especially if you like hiking or heading out in the evening.
Transition to Autumn Conditions
The cooling trend really picks up after Labor Day. By October, average highs in Manchester usually reach around 16°C (60°F). Lows dip down into the single digits Celsius (40s°F), which feels like quite a change from just a month before.
Up north, Berlin often gets frost before October wraps up. It’s not unheard of for folks to wake up to icy windshields by then.
You probably won’t see snow in September, but by late October, some of the higher spots might catch a light dusting. If you’re heading into the White Mountains, this early shift matters—a sunny morning can turn chilly fast.
Winds start picking up a bit in autumn too. In Portsmouth, average wind speeds climb from about 9 kph in August to 13 kph in October. The breeze feels sharper, especially if you’re anywhere near the coast.
Rainfall usually jumps in October compared to September. Coastal areas often get 100 mm or more, so you’ll want to keep an umbrella handy. The combo of rain and cooler temps makes late fall a lot wetter and chillier than early September.
Daylight keeps shrinking, dropping to about 11 hours in October. Those shorter days and cooler evenings really drive home that summer’s over and autumn’s here, whether we’re ready or not.