Fall in Helsinki really feels like a turning point. The long, bright days of summer slip away, and suddenly there’s a crispness in the air. You’ll notice cooler temperatures, lots of clouds, and regular rain as the weeks go by. The change doesn’t come out of nowhere, but it’s steady enough that you can plan for it if you know what you’re in for.
In September, you might still catch some mild days, but by October and November, the chill creeps in. Highs often hover in the single digits Celsius. Rain shows up often, and the Baltic Sea cools fast, making everything feel even damper. You’ll want to dig out your layers and waterproofs if you plan to be outside much.
This season really shows a different side of Helsinki. Parks glow gold, the air feels sharper, and the weather starts to shape your daily plans. If you’re curious about average temperatures, rainfall, or how the sea affects daily life, Helsinki’s fall weather sets a clear beat for travel and routines.
Overview of Fall Weather in Helsinki
Fall in Helsinki means shorter days, cooler air, and a shift from mild conditions to early winter cold. Expect more cloud cover, a growing chance of snow by late fall, and daylight that drops fast. These changes make autumn a time of quick transitions in southern Finland.
Typical Weather Patterns
In fall, daily highs in Helsinki drop from about 63°F (17°C) in September to around 35°F (2°C) in November. Nights fall from the upper 40s °F (about 9°C) to below freezing.
Clouds roll in fast. Early September might still have some clear spells, but by late November, overcast skies are the norm. Rain falls often in September and October, and snow starts showing up more in November.
Precipitation shifts as the season goes:
- September: mostly rain
- October: rain with some wet snow
- November: more snow, some days fully snowy
Winds pick up too, usually 8–11 mph (13–18 km/h), blowing in from the west or south. The Baltic Sea keeps things damp, which adds to the chill.
Transition from Summer to Autumn
The slide from summer into fall comes with a big drop in daylight. In early September, you still get over 14 hours of light, but by late November, it’s down to just 6–7 hours. Sunsets creep earlier, and by late November, it’s dark by mid-afternoon.
Water in the Gulf of Finland cools from around 60°F (16°C) in early September to about 41°F (5°C) by late November. That extra chill from the sea means more clouds and wind.
The growing season wraps up by early October. In September, you might see green leaves, but by late October, most trees are bare. Snow can start to show up in November, hinting that winter’s just around the corner.
Comparison to Other Seasons
Compared to summer, fall in Helsinki feels much cooler and darker. Summer highs can hit 70°F (21°C), but in fall, it drops quickly into the 40s and 30s °F (4–2°C). The sunlight fades faster than it does in spring.
Winter gets much colder and snowier than fall. In January, highs average only around 27°F (-3°C), and daylight shrinks to less than 6 hours. Fall sits in the middle, with a mix of rain and snow.
Spring is different because temperatures rise more slowly, and daylight grows bit by bit. Fall, on the other hand, loses warmth and light quickly. It’s probably the most changeable stretch of weather all year in Helsinki.
Average Temperature in Helsinki During Fall
Temperatures in Helsinki drop steadily through fall, starting with mild September days and sliding to near-freezing conditions by late November. Days get shorter, nights get cooler, and clouds move in as fall goes on.
Monthly Temperature Trends
In September, average highs sit near 17°C (63°F), with nights dipping to about 10°C (50°F). Early on, it can still feel pretty comfortable.
By October, things cool off fast. Highs average around 10°C (50°F), and lows drop to about 5°C (41°F). You’ll need a jacket, and you might spot some frost in the mornings.
November really brings the cold. Highs average only 4°C (39°F), and lows hover near 0°C (32°F). Snow can show up late in the month, but rain and gray skies stick around.
This steady cooling makes fall a true transition period for Helsinki’s weather.
Daytime and Nighttime Differences
Early fall days can feel mild, especially if the sun’s out. In September, you might get by outdoors without heavy layers, but evenings cool off fast.
In October, the gap between day and night grows. It’s common to see a 5–7°C (9–12°F) drop from afternoon to early morning. Nights can feel damp and chilly, even if the day wasn’t too bad.
By November, day and night temps are both cold. Nights often dip below freezing, and daytime highs might not climb above 4°C (39°F). With less daylight, evenings feel even longer and colder.
Historical Temperature Averages
Long-term records show fall in Helsinki always cools down, year after year. The city’s spot on the Gulf of Finland keeps things from getting too extreme, but the downward trend is dependable.
Average highs:
- September: ~17°C (63°F)
- October: ~10°C (50°F)
- November: ~4°C (39°F)
Average lows:
- September: ~10°C (50°F)
- October: ~5°C (41°F)
- November: ~0°C (32°F)
These numbers help you figure out what to wear and what activities make sense. Since the drop is steady, you’ll want to prep for mild starts and almost-winter by the end.
Precipitation and Rainfall Patterns
In the fall, Helsinki gets frequent precipitation, shifting from light rain early on to sleet and snow by late November. The type and amount of precipitation really depends on how cold it gets, so you’re always in that in-between zone from late summer rain to winter snow.
Rainfall Frequency and Amount
Rain sticks around in September and October. Helsinki usually sees 50–70 mm of precipitation per month during these months. November is a bit drier if you only count rain, but total precipitation doesn’t drop much once you factor in snow.
You’ll notice rain on a lot of days, but it’s not always heavy. Most autumns bring 15–20 days with measurable precipitation per month. So, expect it to be damp often, even if it’s just light or moderate showers.
Compared to summer, rain isn’t as intense, but cloudy, wet days happen more. Waterproof clothing is usually more helpful than an umbrella, since the wind can make umbrellas tricky near the coast.
Chance of Snow and Mixed Precipitation
By late October, temperatures fall enough for mixed precipitation. You might get rain that turns into sleet or wet snow, but it usually melts quickly.
November is when accumulating snow shows up for the first time, though it can still flip back to rain if it’s warm enough. Early snows are wet and slushy, so sidewalks can get slippery.
Expect to see rain, sleet, and snow all in the same week, especially in November. Good shoes with grip come in handy, since streets can go from wet to icy fast. Snow is usually shallow at this point, but it’s a sign that winter’s coming.
Notable Wet and Dry Periods
Helsinki’s fall doesn’t have a clear wet or dry season, but there are patterns. September often brings leftover summer rain, so it’s usually one of the wetter fall months. October stays unsettled, with plenty of rain and more clouds.
November feels drier if you only count rain, but snow starts to take over. The total moisture doesn’t change much, but it just comes as snow instead of rain. That’s why November might feel less rainy but still damp and cold.
If you look at the whole year, fall sits between the rainy summer peak in July and the snowy winter months. So, you should expect regular precipitation and not count on long dry spells.
Humidity, Wind, and Atmospheric Conditions
Fall in Helsinki means higher humidity, stronger winds, and less daylight than summer. These changes make the air feel colder, affect how comfortable it is outside, and cut down your sunlight each day.
Typical Humidity Levels
Humidity climbs through fall. In September, it averages around 75–80%, but by November, it’s often close to 90%, so the air feels damp and heavy.
This high humidity mixed with cooler air makes even mild days feel chillier. You might notice more condensation on windows and a bigger chill in the evenings.
More moisture also means more clouds and a higher chance of fog, especially late in the season. If you’re outside a lot, dressing in layers that handle dampness is smart. Waterproof jackets become more important by October and November.
Wind Speeds and Directions
Winds get stronger as fall goes on. Typical wind speeds are 12 to 18 km/h (7 to 11 mph), but storms can bring higher gusts.
Helsinki’s spot on the Gulf of Finland means winds come from the south and southwest, bringing milder but wetter air. Later in fall, winds from the north show up more, bringing cold air from inland Finland and the Baltic.
Breezy days feel colder than the thermometer says, especially by the water. Windproof jackets and hats are a good idea if you’re walking near the harbor or spending a lot of time outside.
Cloud Cover and Sunshine Hours
Fall gets noticeably darker. In September, you might still get 5–6 hours of sunshine per day on average, but by November it drops to less than 1–2 hours.
Clouds build up as fall goes on. Early fall skies are partly cloudy about half the time, but by late fall, overcast days make up nearly 70% of the month.
Heavy clouds, short days, and high humidity make November feel especially gloomy. If you’re visiting, plan for indoor activities and maybe bring a light for afternoon walks.
Sea Temperature and Water Conditions
The water in Helsinki cools off fast once summer’s over. Early fall still has fairly mild sea temperatures, but by late autumn, the Gulf of Finland gets cold and swimming becomes more of a dare. The shift from refreshing to bracing happens quickly, so comfort and safety really depend on timing.
Average Sea Temperature in Autumn
In September, the average sea temperature near Helsinki sits around 15°C (59°F). That’s about as warm as it gets and just barely comfortable for swimming without a wetsuit.
By October, the sea cools to about 10°C (50°F). At that point, it feels pretty cold, and most people don’t stay in long.
In November, water temps drop further to about 7°C (45°F). That’s really cold for swimming, and most folks avoid it unless they have serious thermal protection.
| Month | Avg. Sea Temp. |
|---|---|
| September | 14.9°C |
| October | 10.2°C |
| November | 6.8°C |
These are long-term averages, so the actual day-to-day temps might shift a bit.
Swimming and Water Activities
If you want to swim in Helsinki during autumn, September is honestly your best bet. The water stays cool, sure, but you can handle short swims—especially if the sun decides to come out.
By October, most people just stop jumping into the sea. At 10°C, the water chills your body pretty fast. If you’re thinking about staying in for more than a dip, you’ll need a wetsuit.
In November, only the bravest cold-water fans keep swimming. The temperature drops to around 7°C, and that can hit you with cold shock if you’re not ready for it. Most folks just stick to coastal walks, snapping photos, or soaking in the sea views instead of actually getting in.
Let safety lead your decisions. Limit your time in the water as it gets colder, and grab the right gear if you want to stretch out your swim season.
Travel Tips and What to Expect in Fall
Fall in Helsinki sneaks in with shorter days, cooler temperatures, and a back-and-forth between rain and early snow. You’ll notice daylight shrinking, the air turning crisp, and way fewer crowds. It’s a good time for sightseeing or getting outdoors, as long as you’re ready for the weather.
Recommended Clothing
During fall, Helsinki’s temperatures usually land between 5°C and 10°C (41°F to 50°F) in early October. By November, it’s flirting with freezing. Rain happens a lot, and northern winds can bite.
Bring layered clothing so you can deal with whatever the sky throws at you. You’ll want a waterproof jacket, a warm sweater, and a scarf. Once late fall hits, mornings get frosty, so gloves and a hat come in handy.
For shoes, pick something water-resistant with solid grip, since sidewalks might be wet or icy. You probably don’t need a heavy winter coat until late November, but a mid-weight insulated jacket is a smart move.
Popular Activities and Events
Fall gives you a window to explore Helsinki’s outdoor spots before winter takes over. Central Park and Seurasaari Island are both great for wandering through autumn leaves. If you want a quick escape, Nuuksio National Park is only about 30 minutes away and offers hiking trails with some pretty colorful forests.
Culture doesn’t slow down, either. The Helsinki International Film Festival rolls in September for movie lovers, and then concerts and art exhibitions pop up through October and November.
Saunas never go out of style here, but cooler weather makes them extra tempting. You can check out a public sauna like Löyly by the sea or Kotiharju in the Kallio district.
Best Times to Visit Helsinki in Autumn
If you want to catch the fall foliage, try visiting in late September or early October. Helsinki and the rest of southern Finland burst into color then, with birch and maple trees showing off in bright yellow and orange.
By late October, daylight slips away earlier, and sunset can creep up before 5 PM. November rolls in colder and darker, and sometimes you’ll even see some early snow. Fewer tourists come during this stretch, so you might breeze through museums and attractions.
Summary table of fall travel timing:
| Period | What to Expect | Travel Advantage |
|---|---|---|
| Late Sept–Early Oct | Mild temps, peak foliage, longer daylight | Best for outdoor walks and parks |
| Mid–Late Oct | Cooler, more rain, shorter days | Balanced mix of culture, outdoors |
| November | Cold, early snow, fewer tourists | Quiet atmosphere, indoor focus |