Halloween in Pennsylvania is more than just costumes and candy—it’s a bit of a weather gamble. Some years, the air feels crisp and mild, but other times, you’ll shiver and wish you’d grabbed a heavier coat. Most years, you’ll see daytime highs in the 50s and lows in the 30s across much of the state on October 31.
You’ll notice the weather shifts depending on your location. Philadelphia and the southeast usually stay warmer, but Erie and the northern tier can get much colder. Rain can show up any year, and every so often, snow surprises everyone on Halloween night.
Knowing what to expect helps you plan, whether you’re out trick-or-treating or heading to an event. Let’s break down temperature trends, rainfall, cloud cover, wind, and even the slim but real chance of snow, so you’re not caught off guard by Pennsylvania’s late October mood.
Typical Halloween Weather in Pennsylvania
When you plan for Halloween in Pennsylvania, you should expect cool air and shorter days. The weather changes fast this time of year, and past records show both chilly nights and the occasional warm afternoon.
Average High and Low Temperatures on October 31
On October 31, average high temperatures in Pennsylvania usually range from the 50s in the north and west to the 60s in the southeast.
In Philadelphia, highs often hit the mid-60s. Erie or Scranton, though, usually top out in the low- to mid-50s.
Average lows often dip into the 30s and 40s across most of the state. Northern spots can see frost by late October, while the south stays a bit milder.
You’ll probably want a jacket for trick-or-treating, especially after sunset.
Temperature swings are pretty common. Some years, you’ll get an afternoon close to 70°F, but other years, highs might not even hit 50°F.
Regional Differences Across Pennsylvania
Pennsylvania’s geography really shapes Halloween weather. The southeast, including Philadelphia and the Delaware Valley, usually feels warmest. Highs in this region hit the mid-60s, and lows stick around the mid-40s.
The northwest near Lake Erie is cooler and cloudier. Erie often gets highs in the low-50s, with lake-effect clouds adding a damp vibe.
The central mountains, like State College and Altoona, land somewhere in the middle, with highs in the mid-50s and lows near freezing.
In the southwest, including Pittsburgh, afternoons can feel mild, but evenings cool off quickly. Trick-or-treaters here usually deal with temps in the low- to mid-50s by nightfall.
It pays to check your local forecast instead of relying on state averages.
Historical Weather Patterns for Halloween
Weather records in Pennsylvania show that Halloween has delivered all kinds of conditions. The warmest Halloweens have hit the upper 70s or even low 80s in spots like Philadelphia and Harrisburg.
The coldest years dropped into the 20s at night, especially up north and out west.
Rain is a regular part of the picture, but it doesn’t show up every year. On average, there’s about a 30–40% chance of measurable precipitation on October 31 across most of the state.
Snow is rare, but it has happened in higher elevations and the northwest.
Precipitation and Rainfall Trends
Halloween in Pennsylvania can swing from dry evenings to damp, drizzly ones. Rain isn’t a given, but it’s common enough that you should plan for it.
Historical records say light rain is more likely than heavy downpours, though every now and then a big storm rolls in.
Chance of Rain on Halloween
Your odds of getting rain on Halloween depend on where you are. In many central and eastern cities, rain has fallen on about 3 to 4 out of every 10 Halloweens.
Western Pennsylvania, especially near Lake Erie, has slightly higher odds thanks to lake-effect weather.
Most years, you’ll get dry skies or just a trace of rain. For example, Erie has seen measurable rain on about a third of past Halloweens.
Philadelphia tends to have fewer rainy evenings, but sudden showers can still pop up.
Cloud cover usually increases in late October, which bumps up the chance of light rain. Snow is rare, but isolated flurries have shown up in northern counties during colder years.
Average Rainfall Amounts
Rainfall on October 31 is usually pretty light. Across most of Pennsylvania, the average precipitation is about 0.10 inches.
Most years, you’ll see either no measurable rain or just a quick shower.
When it does rain, it’s often drizzle or a short-lived shower. These don’t usually last all evening.
In central and northeast Pennsylvania, Halloween rain is often less than a quarter inch. It might dampen the sidewalks, but flooding isn’t really a worry.
Snowfall is rare, but not impossible. Higher elevations and lake-effect regions have seen a dusting of snow on Halloween, though it usually melts fast.
For most people, a light jacket and maybe an umbrella will do the trick.
Notable Wet Halloweens
Most Halloweens stay on the dry side, but a few years have turned out soggy. In 2019, parts of Ohio and western Pennsylvania got over 1.5 inches of rain on October 31, making it one of the wettest in recent memory.
In 1993, Cleveland and nearby spots saw more than 4 inches of snow mixed with rain. Pennsylvania has had heavy rain events over an inch once or twice a decade.
These especially wet years usually show up when strong frontal systems pass through. If a cold front rolls in on Halloween, you might get steady rain or even a rain-snow mix in the north.
Most years, though, rain is light and doesn’t stick around for long.
Cloud Cover and Sky Conditions
Late October in Pennsylvania brings a mix of clear skies and clouds. The region really matters here—western spots like Pittsburgh and Erie get more overcast days than eastern cities like Philadelphia.
These patterns affect visibility, comfort, and how much fun outdoor events feel on Halloween.
Likelihood of Clear or Cloudy Skies
You can expect a decent chance of partly cloudy to mostly cloudy skies around Halloween. In eastern Pennsylvania, skies are clearer more often, with Philadelphia getting about 60% of days in late October that are clear or partly clear.
Western and northern areas, including Pittsburgh and Erie, have more cloud cover. In these places, skies are clear or partly clear closer to 50% of the time, and Erie tends to be even cloudier thanks to the lake.
Even on cloudy days, it’s not always fully overcast. Many afternoons still get breaks in the clouds, especially after a front moves through.
You should expect conditions to change quickly, since fall weather systems can shift cloud cover fast.
Impact on Visibility and Outdoor Activities
Clouds can make evening hours feel darker, especially with early sunsets in late October. Daylight drops to about 10–11 hours, so a cloudy sky can make dusk arrive even faster.
For trick-or-treating or fall festivals, cloudy weather might lower visibility along streets and sidewalks. Reflective clothing or extra lighting can help keep everyone safe.
If you’re hoping to stargaze or snap nighttime photos, clearer skies are more common in the east and central valleys. Lake-effect clouds in the northwest often block the view.
Even when skies aren’t perfectly clear, thin clouds can still let some moonlight through and brighten up outdoor activities.
Wind and Evening Temperature Drop
Halloween weather in Pennsylvania usually brings light to moderate breezes and a steady temperature drop after sunset. These changes can really affect how comfortable you feel outside.
Typical Wind Speeds and Gusts
You’ll usually get light to moderate winds in late October. Average wind speeds run from 5 to 12 mph across most areas.
Open spots like farmland or ridge tops can get gusts up to 15–20 mph.
In cities like Philadelphia or Pittsburgh, buildings block some wind at street level. Still, gusts can whip between tall buildings and catch you off guard.
Winds blow from the west or northwest most of the time, especially after a cold front passes. These breezes make it feel colder than the thermometer says.
Wearing layers that block wind helps keep you comfortable.
Strong storms aren’t common on Halloween, but a breezy evening can make lightweight costumes or decorations tough to manage. It’s smart to secure outdoor displays so they don’t blow away.
Temperature Changes After Sunset
Temperatures in Pennsylvania drop quickly after sunset in late October. Afternoon highs might reach the 50s or 60s, but by evening, readings often slide into the 40s before midnight.
In northern areas like Erie or Scranton, the drop can be sharper, sometimes landing in the upper 30s by late evening.
Philadelphia and the southeast usually stay a bit warmer.
Clear skies let heat escape fast, so cooling speeds up. Cloud cover slows the drop, making temperatures steadier.
You’ll notice the chill most if you’re walking between neighborhoods or standing around outside. Gloves, hats, and an extra layer help you stay warm after dark.
Even small elevation changes, like valleys versus hilltops, can make a difference in nighttime temperatures.
Snowfall Possibilities on Halloween
Snow on Halloween in Pennsylvania is rare, but it’s happened. Most years bring chilly nights and dry weather, but some regions—especially up north or in higher elevations—have seen measurable snow.
Frequency of Snowfall Events
Historical data shows your chance of snow on Halloween in Pennsylvania is very low. In most spots, the probability is less than 5%.
That means you might see snow on Halloween once in several decades.
Snow is more likely in the northern tier and higher elevations, where cold air shows up earlier. Even there, the odds are slim, and most years pass without any flakes.
Cities like Philadelphia and Pittsburgh almost never record snow on Halloween, with highs in the 50s and lows in the 30s.
Meteorologists count snow when at least 0.1 inches fall on the day or 1 inch sits on the ground in the morning. These conditions are unusual this early, since October brings more rain than snow.
Notable Snowy Halloweens
A few Halloween dates in Pennsylvania stand out for snow. The biggest was the October 2011 storm, which dumped over a foot of snow in parts of the Northeast and hit northeastern Pennsylvania hard.
That storm caused tree damage and power outages, since many trees still had leaves.
Other years brought lighter events, usually tied to lake-effect snow up near Erie. These tend to be flurries or a dusting, not big accumulations.
In central and southern Pennsylvania, snow on Halloween is so rare that plenty of people have never seen it. When it does happen, it’s usually a mix of rain and snow showers, with little impact on trick-or-treating.
Weather Preparation Tips for Halloween
Temperatures in Pennsylvania at the end of October can swing a lot, and rain or wind can add to the challenge. Planning ahead helps you stay comfortable while keeping costumes practical and safe.
Dressing for Varying Temperatures
Late October evenings in Pennsylvania can swing anywhere from the low 40s to the mid-60s. You’ll want to plan for layers, since the temperature can drop fast once the sun goes down.
A thin base layer under your costume usually keeps you warm without messing up your look. For kids, fleece-lined leggings or a simple long-sleeve shirt under their costume does the trick.
Adults might grab a light jacket or a sweater, maybe in a neutral color so it doesn’t stand out. If you’re somewhere colder, like the mountains or up north, don’t forget gloves and a hat.
Shoes matter more than you might think. Sidewalks and lawns get damp or uneven, so closed-toe shoes or boots are a smart move. Thin costume shoes just don’t cut it—your feet end up cold and sore.
Here’s a quick reference for layering:
| Temperature Range | Clothing Tips |
|---|---|
| 60s°F | Light costume layers, optional jacket |
| 50s°F | Long sleeves, leggings, light sweater |
| 40s°F | Base layer, fleece or coat, gloves optional |
Planning for Rain or Wind
Showers pop up a lot in late October, and wind really makes it feel colder than what the thermometer says. Honestly, you should get ready for both, even if the weather app says it’ll stay clear.
Go ahead and toss some lightweight ponchos or umbrellas in your bag, just in case you get caught in sudden rain. Ponchos work better for kids since their hands stay free.
If you’re dealing with costumes, pick water-resistant fabrics or throw a clear raincoat over the outfit so everyone can still see it.
Wind messes with masks, hats, and capes more than you’d expect. Try using clips, ties, or even a few safety pins to keep things from flying off.
Skip long, trailing fabric that could snag or trip someone when it’s gusty out.
When the wind really picks up, you might want to keep trick-or-treating close to home. Shorter routes mean kids won’t get too cold or worn out.
Always check the local forecast before you leave. That way, you can change your plans if the weather decides to surprise you.