Click on a day for an hourly weather forecast
The weather in Istanbul in September is hot. The average temperatures are between 21°C and 25°C.
You can expect about 3 to 8 days of rain in Istanbul during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Istanbul in September 2025.
If you’re planning to visit Istanbul in the near future, we highly recommend that you review the 14 day weather forecast for Istanbul before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 9° / 5° | 8 | 17 | 5 | 103 mm | Awful | Istanbul in January |
| February | 10° / 6° | 7 | 19 | 3 | 90 mm | Awful | Istanbul in February |
| March | 12° / 7° | 7 | 23 | 2 | 84 mm | Awful | Istanbul in March |
| April | 16° / 10° | 5 | 25 | 0 | 67 mm | Good | Istanbul in April |
| May | 22° / 15° | 5 | 26 | 0 | 62 mm | Good | Istanbul in May |
| June | 26° / 20° | 4 | 26 | 0 | 64 mm | Perfect | Istanbul in June |
| July | 28° / 23° | 1 | 30 | 0 | 28 mm | Perfect | Istanbul in July |
| August | 28° / 23° | 1 | 30 | 0 | 19 mm | Perfect | Istanbul in August |
| September | 25° / 21° | 3 | 27 | 0 | 63 mm | Perfect | Istanbul in September |
| October | 20° / 16° | 4 | 27 | 0 | 99 mm | Good | Istanbul in October |
| November | 16° / 13° | 4 | 26 | 0 | 65 mm | Good | Istanbul in November |
| December | 11° / 8° | 7 | 22 | 1 | 100 mm | Bad | Istanbul in December |