Istanbul weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Excellent
Best time to visit: May – September
What is the weather like in Istanbul in September?
In September, Istanbul is warm: daytime highs average 24 °C, and nights cool down to about 19 °C. The sea averages 22.6 °C – refreshing for a swim. The sun shines for around 7 hours a day. Rain falls on about 7 days, adding up to 47 mm. All in all, September is an excellent month for a holiday in Istanbul.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 93 | 88 | 77 |
| Day | 28° | 24° | 19° |
| Night | 22° | 19° | 15° |
| Sea | 24° | 23° | 19° |
| Sun | 9 h | 7 h | 5 h |
| Rain days | 3 | 7 | 9 |
More details for September
- Daylight
- 12 h 32 min06:43 – 19:16
- UV index
- 6 · highclear sky, noon (estimate)All months
- Muggy days
- 5 daysdew point 18 °C or more
- Wind
- 22 km/haverage daily peak
- Cloud cover
- 35 %on average
- Hot days
- 0 days30 °C or more
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+3Europe/Istanbul
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %68 %
- Few rainy daysweight 30 %80 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
Istanbul in September: quick answers
Is Istanbul hot in September?
Warm rather than hot: in September, daytime highs in Istanbul average 24 °C and nights cool to about 19 °C.
Can you swim in Istanbul in September?
Yes. In September the sea averages 22.6 °C – refreshing for a swim.
Does it rain much in Istanbul in September?
Rain falls on about 7 days, adding up to 47 mm.
Istanbul month by month
The whole year in IstanbulAll destinations: TurkeyWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0)