When you’re planning for Halloween in California, the weather can really shape how your evening goes. Most October 31sts bring mild afternoons with temperatures in the 60s to 70s in many cities, but things cool off fast after sunset—think 50s or even 40s. Costumes usually need a light jacket once the sun disappears.
California stands out because conditions change so much depending on where you are. Coastal spots often stay cool and breezy, while inland valleys feel warmer during the day but get chilly at night.
In the mountains, nights can dip near freezing, which gives Halloween a totally different vibe.
Knowing these weather patterns helps you get ready for trick-or-treating, outdoor events, or travel. Want a crisp autumn night in Northern California? Or maybe a warmer evening in the south? You’ll find all kinds of Halloween weather across the state.
Typical Halloween Weather in California
Most years, you’ll get mild days, cooler nights, and only the occasional rain in late October. But conditions really depend on whether you’re near the coast, inland, or out in the desert.
Temperature Ranges Across the State
Late October daytime highs usually land in the 60s and low 70s°F for most cities. Sacramento often hits around 70°F, while Los Angeles averages a bit warmer in the mid-70s.
San Francisco stays cooler, hanging out in the low to mid-60s.
Inland valleys like Fresno or Riverside keep the warmth longer, with highs close to 75°F. Desert spots, like Palm Springs, can still get into the 80s, but evenings cool off quickly.
Northern coastal towns, like Eureka, stay much cooler, usually in the upper 50s. So, you might wear short sleeves in one place and need a jacket just a few hours away.
Precipitation Patterns and Rain Chances
Rain doesn’t show up often on Halloween in most parts of California, but it’s not impossible. Coastal and northern areas have a higher shot at showers compared to the south.
Sacramento, for example, averages just a small risk of rain on October 31, but early fall storms sometimes bring light showers. Santa Rosa in the North Bay gets rain about half the time, but Los Angeles and San Diego usually stay dry.
Snow can show up in the Sierra Nevada by late October, mostly at higher elevations. If you’re planning to drive through mountain passes, check the forecast—things can change fast.
Daytime Versus Evening Weather Trends
During the day, most places feel great for outdoor stuff like festivals or pumpkin patches. But by evening, temps drop fast, especially inland and up north.
Cities like Sacramento and San Francisco often see nighttime lows in the 40s and 50s°F. Southern California stays milder, with lows in the upper 50s to low 60s.
Desert regions cool off even faster, sometimes dropping 25 degrees or more from the afternoon high.
If you’re trick-or-treating or heading to an evening event, bring a light jacket or sweater. The chill after sunset can catch you off guard, even if the day felt warm.
Regional Weather Differences on Halloween
California’s late October weather changes a lot depending on where you are. Elevation, how far you are from the coast, and local climate patterns all play a part.
Northern California Conditions
Northern California usually brings cooler evenings and a better chance of fog or light rain. Coastal towns like Crescent City or Eureka can get damp, cloudy skies, but inland valleys like Napa or Sonoma tend to stay drier.
Daytime highs often range from the upper 60s to mid-70s, but nights cool off quickly. By sunset, it’s often in the 50s, and some valleys drop into the 40s before midnight.
If you’re in higher elevations, like the Sierra Nevada foothills, expect even colder weather. Lows can dip into the 30s, and frost isn’t rare.
Dressing in layers really helps you stay comfortable during outdoor Halloween fun.
Central Valley and Inland Areas
The Central Valley usually gets mild afternoons and cool evenings in late October. Sacramento and Fresno reach highs in the low 70s, which is about average.
Warm sunny days quickly give way to chilly nights.
By trick-or-treat time, temperatures usually sit in the upper 50s to low 60s. Overnight lows can fall into the 40s, especially out in the country.
Dry air makes the evenings feel even cooler than the thermometer says.
Inland valleys farther south, like Bakersfield, hold onto warmth a bit longer. Highs might reach the mid-70s, but after sunset, the temperature drops fast.
You’ll want to plan for a quick cool-down if you’re staying out after dark.
Southern California Weather
Southern California is warmer and drier than the rest of the state around Halloween. Los Angeles and Orange County often see highs in the mid-70s to low 80s.
Inland spots like Riverside or San Bernardino sometimes climb into the upper 80s.
Evenings stay more comfortable here compared to the north. Most places hold in the 60s through early evening, with coastal areas closer to 60 and inland valleys dropping into the 50s later at night.
Sometimes, Santa Ana winds bring very dry air and warmer-than-normal weather. These winds can raise fire danger and keep nighttime temps from falling as much as usual.
Coastal Versus Inland Microclimates
California’s coast and inland valleys really show off their differences. Along the coast, temps stay moderate—usually around 65–70°F during the day and 55–60°F at night.
The ocean keeps things steady, and fog isn’t as common in late October as it is in summer.
Inland areas, even just a short drive away, warm up and cool down much faster.
For example:
| Region | Afternoon Highs | Evening Temps | Overnight Lows |
|---|---|---|---|
| San Francisco | 68–72°F | ~60°F | 50s |
| Napa Valley | 72–76°F | 55–60°F | 40s |
| Los Angeles Basin | 75–82°F | 60–65°F | Upper 50s |
If you’re planning outdoor activities, keep in mind that inland valleys lose heat quickly after sunset. Near the coast, you’ll enjoy more stable, mild conditions, but inland, you’ll need extra layers once the sun goes down.
Sierra Nevada and Mountain Areas
In the Sierra Nevada, late October usually means colder nights, early-season snowfall, and changing travel conditions.
You’ll notice clear differences between higher elevations, where snow is common, and lower foothill zones, where it’s chilly but less severe.
Halloween Snowfall and Cold Weather
Snowfall in the Sierra Nevada often starts by late October, especially above 6,000 feet. Not every year brings heavy storms, but light to moderate snow is pretty common.
Mountain passes can see early closures or chain requirements.
At higher spots like Donner Pass or Tioga Pass, snow can stick around and create icy conditions, even when the sky looks clear. Lower foothill towns usually just get rain or cold drizzle.
If you’re hiking or camping, expect wet trails, slick granite, and poor visibility during storms.
Early winter weather can show up fast, so prep for snow even if the forecast only calls for rain.
Travel Considerations and Safety
Mountain travel in late October takes extra caution. Roads like Interstate 80 and Highway 50 often need chains during early snow.
Delays happen a lot, so give yourself more time to get places.
Pack chains, blankets, and extra food and water in your car. Gas stations and services get sparse at higher elevations, so fill up before you head up.
Weather can flip from rain to snow within just a few miles of elevation gain.
If you’re driving at night, watch for black ice in shady spots and on bridges. Even seasoned drivers can get caught off guard when the first snow hits.
Typical Nighttime Temperatures
By late October, nighttime temperatures in the Sierra Nevada often drop below freezing at high elevations. In valleys and passes, lows in the 20s °F (-6 to -2 °C) are common.
Foothill towns may stay in the 30s to low 40s °F (1 to 6 °C).
Cold air settles fast after sunset, especially in canyons and near lakes.
If you’re camping, bring a sleeping bag rated for below-freezing temps.
For day trips, dress in layers. Afternoon highs can still reach the 50s °F (10–15 °C), but temps fall sharply once the sun sets.
Thin gloves, hats, and insulated jackets really help with comfort and safety.
Weather Impacts on Halloween Activities
California’s Halloween weather can shape how you celebrate. Evening temperatures drop quickly after sunset, and some places might see rain or coastal fog.
These conditions can affect how safe, comfortable, and fun your activities turn out.
Trick-or-Treating Safety and Comfort
When you take kids out for trick-or-treating, think about both the temperature and visibility. Coastal cities might feel damp and cool, while inland valleys can go from the 70s in the afternoon down to the 50s by evening.
Chilly air can make long walks uncomfortable if you aren’t dressed in layers.
Rain doesn’t happen often but can still show up, especially in the north. Wet sidewalks get slippery, and mist or fog can make it hard for drivers to see.
Carrying flashlights or putting reflective tape on costumes helps a lot.
Choose routes with good lighting. Neighborhoods with sidewalks and fewer busy streets are safer.
Shorter routes might work better for little kids if it feels colder than you expected.
Outdoor Event Planning
Community events like block parties or pumpkin festivals really depend on the weather. In Southern California, mild evenings usually make outdoor gatherings easy.
Cooler inland valleys and mountain towns, though, often need tents, heaters, or earlier start times to keep everyone comfortable.
Northern California can be less predictable. Light rain or coastal drizzle might interrupt outdoor movie nights or parades.
Having a backup indoor space or renting a canopy helps protect food and decorations.
Timing matters, too. Sunset comes earlier in late October, so planning events before dusk gives you more daylight and warmth.
If your event runs into the evening, extra lighting and warm drinks make things a lot more inviting.
Costume and Clothing Recommendations
Pick costumes that work for temperature swings. Afternoon events might feel warm enough for lighter outfits, but evenings usually need jackets or sweaters underneath.
Kids especially do better with costumes that have room for layers.
In cooler spots, gloves, hats, or scarves in matching colors blend with costumes and keep you warm.
For warmer areas, breathable fabrics help you avoid overheating.
Footwear matters, too. Closed-toe shoes grip better on damp sidewalks and keep feet warmer than sandals.
If rain’s in the forecast, think about waterproof boots.
A small umbrella or poncho can help you stay dry without ruining your plans.
Unusual Weather Events and Historical Trends
Halloween weather in California usually stays mild, but sometimes things get weird. You might run into record warmth, sudden rainstorms, or rare weather extremes that stick out in local memory.
Heat Waves and Unseasonal Warmth
Late October usually brings warm temperatures, but some years hit with unseasonal heat waves. Inland valleys can spike into the 80s or even low 90s, which feels a bit odd for fall.
Coastal areas tend to stay cooler. Still, when Santa Ana winds show up, they push hot, dry air right to the beaches.
These warm spells spark fire weather worries, especially when humidity drops. You might feel strong, dry winds during trick-or-treating, which ramps up wildfire risks.
Southern California gets this pattern the most, but sometimes it stretches up into central regions too.
Not every year brings a heat wave, but California’s warming climate seems to tip the odds toward hotter Octobers. If you look back at past decades, late October now runs noticeably warmer than it did back in the early 1900s.
Rainy Halloweens in Recent Years
Rain doesn’t visit California every Halloween, but it does happen. When Pacific storms roll in early, they can bring showers, thunderstorms, or gusty winds.
These weather swings often mess with outdoor plans, especially up north where the storm track stays more active.
Some years, heavy rain has forced folks to change or even cancel Halloween festivities. Strong cold fronts in late October have brought damaging winds, lightning, and even tornadoes to parts of the state.
Sure, these storms are rare, but they prove that Halloween isn’t always dry in California.
Southern California doesn’t usually get much rain, but coastal spots can still see quick showers. If you’re planning something outside, it’s smart to keep an eye on the forecast. Rain might be infrequent, but it can sneak up fast.
Notable Weather Records
California’s weather history is full of sharp swings in temperature and rainfall. The hottest year statewide was 2014, with an average high of 74.2 °F.
On the flip side, 1911 was the coldest, with daily highs averaging just 68.0 °F.
A few rare events really stand out. People have even reported snow flurries near coastal San Diego, and some late Octobers have lined up with strong Santa Ana winds.
These odd patterns don’t happen every year, but they’re still part of the state’s weather story.
Forecasting and Preparing for Halloween Weather
California’s Halloween weather can flip between clear, mild evenings and chilly nights with a shot at rain in some areas. If you know how to track local forecasts and adjust your plans, you’ll dodge most surprises once you head out.
How to Check Local Forecasts
Start with trusted sources like the National Weather Service, local TV, or regional news. They’ll give you updates on temperatures, rain chances, and wind for your specific area.
Watch for things like:
- Daytime high and evening low temperatures
- Chance of rain or drizzle
- Wind speed and direction
Since most Halloween fun happens in the evening, zero in on the forecast between 5 p.m. and 9 p.m. A warm day—like 72°F in Sacramento—can cool down fast, dropping to the low 50s by night.
Don’t just trust one app. Check radar maps or hourly forecasts for a better sense of when rain might hit or how quickly it’ll cool off.
If you live near the coast or up in the Sierra foothills, weather can shift in a hurry. Checking updates the day before and even the morning of Halloween helps you stay ready.
Adapting Plans for Changing Conditions
You can make Halloween a lot more comfortable if you plan around the weather. If the forecast says rain, grab umbrellas, ponchos, or waterproof bags for candy.
On cooler nights, layer clothes under costumes to stay warm. This way, you don’t have to hide your whole outfit.
Keep a backup plan in mind for indoor activities if outdoor events get delayed. Community centers, shopping malls, or even indoor trick‑or‑treat events usually offer good alternatives when things get wet.
Think about safety on wet roads. Slippery sidewalks and dim lighting can make walking tricky.
Damp costumes don’t help either. Reflective tape, flashlights, and sturdy shoes can really lower your risk.
If you’re driving to a neighborhood or an event, give yourself extra travel time. Rain in the Bay Area or snow in the Sierra tends to slow everything down.
Preparing early keeps you flexible. Who doesn’t want to actually enjoy the evening, right?