Istanbul in September
In September, Istanbul averages 25°C (77°F) during the day and 17°C (63°F) at night, with around 5 days of rain (55 mm total).
High seasonConditions are comfortable for sightseeing without being sweltering. Occasional showers are likely but won't dominate.
September is a great month to visit Istanbul: pleasant temperatures and relatively few wet days.
How September compares to the rest of the year in Istanbul
September is in the middle of the year for warmth in Istanbul (4th of 12) and moderately rainy compared to the rest of the year (9th of 12). Daytime temperature runs 6°C above the annual average (19°C). September runs 4°C cooler than August (29°C) and cools 5°C in October (20°C).
September sunrise & sunset in Istanbul
Times shown for Istanbul local time (Europe/Istanbul), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Istanbul — September
Golden-hour and blue-hour windows for the 15th of September, in Istanbul's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Istanbul in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (High season) and Istanbul's popularity.
Crowds & pricing — September in Istanbul
This is a busy month in Istanbul — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: excellent tourism weather
Sun & mosquito risk — September in Istanbul
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Sea temperature in Istanbul — September
Across the year Istanbul's sea swings from 8.8°C (February) to 24.9°C (August) — September sits at 24.3°C.
Istanbul in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 9°C / 48°F | 3°C / 37°F | 110 mm | 13 | — |
| February | 10°C / 50°F | 3°C / 37°F | 85 mm | 11 | — |
| March | 12°C / 54°F | 4°C / 39°F | 70 mm | 9 | — |
| April | 17°C / 63°F | 8°C / 46°F | 45 mm | 8 | — |
| May | 22°C / 72°F | 12°C / 54°F | 35 mm | 6 | — |
| June | 27°C / 81°F | 17°C / 63°F | 35 mm | 4 | — |
| July | 29°C / 84°F | 20°C / 68°F | 30 mm | 3 | — |
| August | 29°C / 84°F | 20°C / 68°F | 40 mm | 4 | — |
| September | 25°C / 77°F | 17°C / 63°F | 55 mm | 5 | — |
| October | 20°C / 68°F | 13°C / 55°F | 85 mm | 9 | — |
| November | 15°C / 59°F | 9°C / 48°F | 105 mm | 11 | — |
| December | 11°C / 52°F | 5°C / 41°F | 130 mm | 13 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Istanbul in September →
Frequently asked questions
How hot is Istanbul in September?
In September, Istanbul averages a high of 25°C (77°F) and a low of 17°C (63°F) — generally warm.
Does it rain a lot in Istanbul in September?
September sees occasional rain in Istanbul, with about 5 rainy days on average.
Is September a good time to visit Istanbul?
September is warm and mostly dry. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Istanbul in September?
Pack light layers for warm days and cooler evenings. See the full September packing list for Istanbul for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.