Fall in Istanbul feels like a real shift. The city moves from summer’s warmth to cooler, breezier days. You’ll see average daytime highs between 62°F and 73°F (16°C to 23°C) in early fall, but by late November, those highs drop closer to 54°F (12°C). Nights get cooler, though temperatures rarely reach freezing, so exploring Istanbul’s outdoor spaces stays comfortable.
As fall rolls on, the skies get cloudier and rain becomes more likely, especially in November. The Bosphorus brings a crisp breeze, and humidity drops, making the air fresher than in muggy summer. This mix of mild temperatures, shifting skies, and steady winds really shapes daily life in Turkey’s largest city.
The sea around Istanbul cools off quickly. You might swim in September, but by late fall, the water turns chilly. These changes affect coastal activities and influence how you plan your time—maybe you’ll walk through historic districts, relax on café terraces, or prep for wetter, shorter days.
Overview of Fall Weather in Istanbul
Autumn in Istanbul brings cooler air after summer’s heat. Rain falls more often, and daylight starts to wane. Afternoons stay mild to warm, evenings turn cooler, and rainfall steadily increases as winter approaches.
Typical Temperature Ranges
In September, daytime highs usually reach 26 °C (79 °F), while nights fall to about 18 °C (64 °F). October’s highs drop to 21 °C (70 °F) and lows hover around 14 °C (57 °F).
November feels a lot cooler, with average daytime temperatures at 16 °C (61 °F) and nights down to 9 °C (48 °F).
Early autumn feels great for outdoor activities. By late autumn, you’ll probably want a jacket. Warm afternoons and crisp evenings are typical, especially if you’re walking along the Bosphorus or climbing the city’s hilly streets.
The cooling trend means you don’t get wild temperature swings. Fall is moderate, way more consistent than summer’s heat.
Precipitation Trends in Autumn
Rainfall increases as fall goes on. September averages about 40 mm, October jumps to around 57 mm, and November reaches about 62 mm. Showers don’t last long, but sometimes they hit hard, especially later in fall.
Humidity rises too. November averages 76%, while September sits at 67%. On cooler days, especially near the coast, this can make the air feel damp.
Bring an umbrella or a light rain jacket—wet days become pretty common by October and November. After sudden showers, streets can get slippery, so good walking shoes really help if you’re exploring on foot.
Daylight Hours and Sunshine
Daylight shrinks fast in autumn. September gives you about 12.5 hours of daylight, but by November, you get only around 10 hours. This definitely cuts into sightseeing time before evening rolls in.
Sunshine hours drop too. September often brings bright skies, but October and November have more clouds and fewer sunny days.
Even with shorter days, you can still catch clear mornings and golden afternoon light. It’s smart to plan outdoor activities earlier, since evenings come quickly and temperatures drop after sunset.
Monthly Breakdown: September to November
Istanbul’s fall months bring steadily cooler temperatures, less daylight, and more rain. You’ll feel the shift from late-summer warmth in September to much cooler, wetter weather by November.
September Weather Patterns
September in Istanbul still feels like summer, though the heat starts to fade. Highs hover around 24–25°C (75–77°F), and lows are about 20°C (68°F). Humidity stays moderate, and evenings grow more comfortable.
Rainfall picks up compared to August. Expect about 26 mm (1.0 in) of rain over several days, but dry, sunny stretches are still common. Daylight averages 12.5 hours, so you have plenty of time outside.
The sea stays warm, often near 23–24°C (73–75°F). September is one of the last months when swimming along the Marmara and Black Sea coasts feels pleasant.
Sightseeing is great in September—weather is milder, and crowds thin out as peak summer ends. Light clothes work during the day, but bring a light jacket for the evenings.
October Weather Patterns
By October, you’ll notice a clear seasonal shift. Highs fall to about 19–20°C (66–68°F), and nighttime lows dip to around 14°C (57°F). The cooler air makes city walks more comfortable, though you’ll need layers.
Rainfall increases, averaging 42 mm (1.6 in). Showers happen more often, but usually come in quick bursts, not all-day storms. Sunshine drops to about 11 hours, and days start to feel shorter.
The Bosphorus and nearby parks show off early autumn colors, which is great for photography and strolls. Sea temperatures cool to 20–21°C (68–70°F), still okay for some swimmers but not as inviting as September.
Pack both light and warmer clothes, plus an umbrella. October often strikes a nice balance between summer warmth and winter chill.
November Weather Patterns
November really brings out the autumn vibe. Highs reach just 14–15°C (57–59°F), and lows fall to around 9–10°C (48–50°F). Mornings and evenings can feel chilly, especially near the water.
Rainfall keeps rising, averaging 33 mm (1.3 in), and cloudy days become more frequent. Sunshine hours drop below 10 hours, so days feel much shorter.
The sea cools to around 17–18°C (63–64°F), which is usually too cold for swimming. Winds get stronger, especially along the Bosphorus, so you’ll notice brisk conditions outdoors.
November feels more like winter’s doorstep. A medium-weight jacket, comfy shoes for wet streets, and layers help you adjust to changing temperatures.
Humidity, Wind, and Atmospheric Conditions
In fall, Istanbul has moderate humidity, shifting winds, and usually stable visibility. Rain falls more often than in summer, but outdoor activities still feel comfortable, with just occasional weather hiccups.
Average Humidity Levels
Fall humidity in Istanbul runs between 67% and 75%. September is less humid, while October and November see higher levels as the air cools and holds more moisture.
Mornings often feel humid after overnight cooling, but afternoons dry out. That makes midday outdoor activities more pleasant.
Late fall’s higher humidity can make temperatures feel cooler than they are. Layering helps you stay comfortable as the day changes.
| Month | Avg. Humidity |
|---|---|
| September | ~68% |
| October | ~71% |
| November | ~75% |
Wind Patterns in Fall
Winds in Istanbul during fall are moderate and steady, averaging between 14 km/h (9 mph) and 20 km/h (12 mph). September still has summer’s lighter breezes, but by November, gusts pick up, especially near the Bosphorus and the coast.
North and northeast winds dominate, mainly coming from the Black Sea. These can make evenings feel cooler than you’d expect. They also bring in occasional rain showers, especially later in the season.
If you walk along the waterfront or ride a ferry, you’ll notice more wind than in the city’s inner neighborhoods. A light jacket usually does the trick for comfort.
Visibility and Air Quality
Istanbul’s visibility stays around 10 km (6 miles) through fall. You can enjoy views of landmarks and waterways without much fog or haze.
Air quality holds up well during fall. Cooler temperatures and steady winds keep pollution low, unlike summer, when stagnant air can trap smog.
Rain showers now and then help clear the air, leaving things crisp. This combo of clear visibility and manageable humidity makes fall a great time for sightseeing and photography around the city.
Sea Temperature and Coastal Conditions
Istanbul’s waters cool down steadily through fall. Early in the season, the sea feels fine for swimming, but by late autumn, most people stick to the shore. Along the coast, you’ll notice shorter days and more rain.
Average Sea Temperatures
In September, the average sea temperature sits at about 23°C (73°F). That’s warm enough for most swimmers and great for boat trips or coastal walks.
By October, water cools to around 19°C (66°F). Some folks still swim, but the chill becomes noticeable, especially if you stay in the water for a while.
In November, the sea drops to about 15–16°C (59–61°F). The water feels cold, so swimming is rare. Most coastal fun shifts to sightseeing, ferry rides, or just soaking up the sea views from shore.
These changes match the broader seasonal shift in Istanbul’s climate, moving from late summer into the cooler, wetter early winter.
Swimming and Water Activities
If you love swimming, September is your month. The sea stays warm, the weather’s still mild, and you’ll get plenty of sunny days. Beaches and water sports are still on the table.
In October, swimming is possible but less common. The cooler water feels refreshing for short dips, but most visitors prefer walking the Bosphorus or taking boat cruises.
By November, the sea’s just too cold for most. Instead, explore coastal neighborhoods, ride ferries between Europe and Asia, or grab seafood while gazing at the water.
Water activities in fall shift from swimming to soaking in Istanbul’s unique spot between two seas.
How Fall Weather Affects Travel and Activities
Mild temperatures and shorter days shape how you explore Istanbul in autumn. Rain shows up more often later in the season, so you might switch between outdoor walks and indoor cultural stops.
Outdoor Sightseeing and Events
Early autumn, especially September, gives you warm days averaging 22 °C (72 °F) and plenty of sun. It’s honestly one of the best times to visit—you can see landmarks like Hagia Sophia, the Blue Mosque, or Topkapı Palace without summer’s crowds or heat.
By October, highs drop to about 17 °C (63 °F), and rain showers happen more. You can still enjoy ferry rides or stroll historic districts, but you might need to dodge a few wet days.
November brings cooler air, with averages near 12 °C (54 °F). You’ll spend less time outside, but this season is perfect for cultural events, art shows, and food festivals that move indoors as the weather cools.
Museums, bazaars, and mosques stay open all year, so you always have options if rain interrupts your plans.
Packing Tips for Autumn Visits
Pack light layers because daytime and evening temperatures swing a bit. A water-resistant jacket comes in handy for October and November’s rain.
Comfy walking shoes are a must—you’ll spend hours on uneven streets and old sites. In September, short sleeves and a light sweater work, but by late autumn, you’ll want warmer clothes like a fleece or scarf.
Toss in a compact umbrella or rain poncho since showers can show up out of nowhere. If you’re visiting mosques, bring a modest outfit that covers shoulders and legs.
Packing with flexibility keeps you comfortable, whether you’re strolling the Bosphorus in sunshine or navigating a rainy day in the Grand Bazaar.
Comparing Fall to Other Seasons in Istanbul
Fall in Istanbul brings cooler temperatures, shorter days, and more rain than summer, but it’s still milder than winter. It doesn’t have spring’s rapid warm-up, offering a steadier, slower shift in weather that a lot of travelers find comfortable.
Fall vs. Summer Weather
Summer in Istanbul gets pretty hot, with average highs landing somewhere between 25°C and 28°C (77°F–82°F). The humidity isn’t too bad, but those long daylight hours and barely any rain make the city feel dry and bright.
Fall, on the other hand, cools things down fast. Highs drop from 24°C (75°F) in September to just 15°C (59°F) in November.
Rainfall changes a lot between seasons. Summer barely sees any rain, with just 11–32 mm each month.
By November, fall brings more showers, up to 30–40 mm. This means outdoor sightseeing gets a bit unpredictable, though you’ll still find plenty of dry days in September.
If you like fewer crowds and cool evenings, fall can feel way more comfortable than the summer heat. But if you’re all about long beach days or squeezing every bit out of the daylight, summer still wins.
Fall vs. Winter Weather
Winter in Istanbul isn’t as harsh as in many European cities, but it’s still the coldest stretch of the year. December through February usually brings highs around 8°C–11°C (47°F–52°F), and lows hover near 5°C (41°F).
Rainfall peaks in winter, and sometimes you’ll even see a dusting of snow, especially in January.
Fall sits right in the middle. You skip the damp chill and short days of winter, but it’s still way cooler than summer.
In November, you get about 10 hours of daylight, while December drops below 6.
If you’d rather not deal with heavy coats or icy sidewalks, fall makes walking tours and ferry rides a lot easier. Winter can feel more atmospheric, though, especially if you like quiet streets and maybe a little snow on Istanbul’s hills.
Fall vs. Spring Weather
Spring in Istanbul kicks off pretty cool in March, with highs around 12°C (54°F). By May, it usually warms up to about 21°C (70°F).
You’ll notice rainfall drops off as spring goes on, and daylight stretches from 12 hours in March to almost 15 hours in May.
Fall heads in the other direction. The days shrink from 12+ hours in September to less than 10 hours in November.
Rain picks up instead of fading away, and temperatures slip down instead of climbing.
A lot of travelers say spring is one of the best times to visit Istanbul. It’s got that sweet spot of mild weather, longer days, and not too much rain.
Fall still feels comfortable, but you’ll probably get more showers and the sun sets earlier.
You can explore landmarks in both seasons, but spring gives you more daylight if you want to make the most of a full day out.