Türkiye Istanbul Weather in September — Climate Guide
September in Istanbul is Excellent
September is Excellent for Istanbul.
September is Istanbul's optimal post-summer month. 24°C days + 16°C nights + manageable rain. Hotel prices drop 20-30% from August peak.
European school resumes mid-month — crowds drop significantly. Sea temperature still 21°C for last swimming. Outdoor sights + Bosphorus + Princes' Islands at perfect comfort.
Travel score
Early autumn + value returning + Akbank Jazz Festival
September Weather at a Glance
Istanbul in September averages 79°F / 26°C high and 61°F / 16°C low. 9 hours sunshine, 50mm rain, 7 rainy days. Top month of the year — crowds thin + heat eases. Sunrise 6:35 AM, sunset 7:25 PM — daylight 12h 50m.
September Travel Advice
Long-sleeve + T-shirt + light jacket + sneakers. Akbank Jazz Festival (all month, top jazz) + Istanbul Biennial (contemporary art biennial, mid-September-mid-November, every 2 years) + Istanbul Design Biennial (alternates).
Flying In from Overseas
Korea Chuseok holiday — Seoul-Istanbul $1,290-2,050. Week after Chuseok (last week September) is the year's value sweet spot.
September Pricing Trends
Tail-end peak — Sultanahmet 4-star $155-290/night. Beşiktaş 5-star $340-665.
Istanbul September Weather Stats
Avg High
24°C
Avg Low
16°C
Rainy Days
6
50mm total
Sunshine
9h
Daily avg
Humidity
67%
Comfortable
UV Index
7
High
Wind
12 km/h
Gusts 26
Sea Temp
21°C
Avg water temp
Crowds
Busy
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
22 μg/m³
PM10
45 μg/m³
Status
Moderate
Feels-Like Temperature & Wind
Feels like
Daytime
25°C
Nighttime
15°C
Humidity and wind affect how the actual temperature feels.
Wind
12 km/h
Max gust 26 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Best post-summer value
- Crowds drop 30-40%
- Last warm sea + balloon weather
Cons
- Sea cooling (21°C)
- Days getting shorter (12h)
- Late September rain returning
September Events & Festivals
- Tourist crowds reducing post-Labor Day (European school resumption mid-month)
- Hotel prices 20-30% below summer peak
- Best value-to-weather window (post-summer + pre-rain)
- Akbank Jazz Festival all month at Cemil Topuzlu open-air theater
- Istanbul Biennial (contemporary art, every 2 years, mid-September-mid-November)
Istanbul in September — Full Picture
September is Istanbul's optimal post-summer month. 24°C days + 16°C nights + manageable rain. Hotel prices drop 20-30% from August peak.
European school resumes mid-month — crowds drop significantly. Sea temperature still 21°C for last swimming. Outdoor sights + Bosphorus + Princes' Islands at perfect comfort.
Istanbul Biennial (September-November, every 2 years) brings contemporary art to historic venues. Hagia Eirene + Müze Gazhane + Galata Greek School are biennial venues.
What to Wear & What to Pack
T-shirts + light sweater + jeans. Light jacket for cool evenings. Perfect outdoor weather.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
16°C
8°C
9.3/mo
Summer (Jun·Jul·Aug)
27.3°C
18°C
5/mo
Autumn (Sep·Oct·Nov)
Current19°C
12.3°C
9.3/mo
Winter (Dec·Jan·Feb)
9°C
3.7°C
12.7/mo
Istanbul Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 8° | 3° | 13d·91mm | 3.5h | 75% | 2 | Quiet | Low season | |
| 9° | 3° | 12d·78mm | 4h | 73% | 3 | Quiet | Low season | |
| 11° | 4° | 11d·68mm | 5h | 71% | 4 | Moderate | Shoulder | |
| April (Best) | 16° | 8° | 9d·46mm | 7h | 70% | 5 | Busy | Peak |
| May (Best) | 21° | 12° | 8d·36mm | 9h | 70% | 7 | Busy | Peak |
| June (Best) | 26° | 16° | 6d·35mm | 10h | 67% | 8 | Very busy | Peak |
| July (Best) | 28° | 19° | 4d·27mm | 11h | 65% | 9 | Very busy | Peak |
| August (Best) | 28° | 19° | 5d·41mm | 10.5h | 67% | 9 | Very busy | Peak |
| September (Best) | 24° | 16° | 6d·50mm | 9h | 67% | 7 | Busy | Shoulder |
| 19° | 12° | 10d·80mm | 6.5h | 71% | 5 | Moderate | Shoulder | |
| 14° | 9° | 12d·96mm | 4.5h | 75% | 3 | Quiet | Low season | |
| 10° | 5° | 13d·116mm | 3.5h | 76% | 2 | Moderate | Shoulder |
View Other Months
Istanbul September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Istanbul?
Istanbul in September is Excellent. Tourist crowds are busy and flight/hotel prices are shoulder.
What's the average temperature in Istanbul in September?
Istanbul September averages a high of 24°C and a low of 16°C.
Does it rain much in Istanbul in September?
Istanbul September averages 50mm of rainfall over about 6 rainy days.
What should I wear in Istanbul in September?
T-shirts + light sweater + jeans. Light jacket for cool evenings. Perfect outdoor weather.
What time are sunrise and sunset in Istanbul in September?
Istanbul September sunrise is 06:45 and sunset is 19:15, with 12h 30m of daylight.
What's the air quality like in Istanbul in September?
Istanbul September air quality (AQI) averages 60, rated Moderate. PM2.5 averages 22μg/m³.
What activities are recommended in Istanbul in September?
In September, Istanbul is great for Bosphorus + Princes' Islands, Last sea swimming, Outdoor sights all.
Is September peak season in Istanbul?
Istanbul September crowds are busy and prices are shoulder. Advance reservations are strongly recommended.
Best Months to Visit Istanbul
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.