September weather forecast
Istanbul, Turkey

Ships along the coast of the city port of Istanbul, Turkey
Ships along the coast of the city port of Istanbul, Turkey

Weather in September

The first month of the autumn, September, is also a moderately hot month in Istanbul, Turkey, with an average temperature fluctuating between 20.4°C (68.7°F) and 24.3°C (75.7°F).

Temperature

In Istanbul, the average high-temperature in September marginally drops from a warm 27.8°C (82°F) in August to a still moderately hot 24.3°C (75.7°F). In September, the average low-temperature is 20.4°C (68.7°F).

Humidity

The average relative humidity in September in Istanbul is 68%.

Rainfall

In Istanbul, in September, it is raining for 10 days, with typically 26mm (1.02") of accumulated precipitation. In Istanbul, during the entire year, the rain falls for 130.7 days and collects up to 400mm (15.75") of precipitation.

Snowfall

In Istanbul, snow does not fall in April through November.

Sea temperature

In Istanbul, the average water temperature is 22.8°C (73°F).
Note: A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 22.8°C (73°F) water. (FYI: The Olympic swimming competition requires a water temperature between 25°C (77°F) and 28°C (82.4°F).)

Daylight

In Istanbul, the average length of the day in September is 12h and 28min.
On the first day of September, sunrise is at 06:30 and sunset at 19:37. On the last day of the month, sunrise is at 06:59 and sunset at 18:48 +03.

Sunshine

The average sunshine in September in Istanbul is 8.9h.

UV index

In September, the average daily maximum UV index in Istanbul is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the average person.
Note: The daily maximum UV index of 5 in September interpret into the following advice:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.
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FAQ

What is the temperature in September in Istanbul?

In September, the average high-temperature is 24.3°C (75.7°F), and the average low-temperature is 20.4°C (68.7°F). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in August is appraised at 30°C (86°F).

What is the average humidity in September in Istanbul?

The average relative humidity in September is 68%.

How much does it rain in Istanbul in September?

In Istanbul, in September, during 10 rainfall days, 26mm (1.02") of precipitation is typically accumulated.

When it does not snow in Istanbul?

April through November are months without snowfall in Istanbul.

How warm is the water in September in Istanbul?

In September, the average sea temperature is 22.8°C (73°F). A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 22.8°C (73°F) water.

What is the average length of the day in September in Istanbul?

In Istanbul, Turkey, the average day length in September is 12h and 28min.

When are sunrise and sunset in September in Istanbul?

In September, on the first day of the month, sunrise is at 06:30 and sunset at 19:37. On the last day of the month, in Istanbul, Turkey, sunrise is at 06:59 and sunset at 18:48 +03.

How long on average sun shines in September in Istanbul?

In September, the average sunshine duration in Istanbul is 8.9h.

What is the UV index intensity in September in Istanbul?

The average daily maximum UV index in September in Istanbul is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.

Average temperature in September
Istanbul, Turkey

Average temperature in September - Istanbul, Turkey
  • Average high temperature in September: 24.3°C

The warmest month (with the highest average high temperature) is July (27.9°C).
The month with the lowest average high temperature is January (8.5°C).

  • Average low temperature in September: 20.4°C

The month with the highest average low temperature is August (23.3°C).
The coldest month (with the lowest average low temperature) is January (5.3°C).

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Average pressure in September
Istanbul, Turkey

Average pressure in September - Istanbul, Turkey
  • Average pressure in September: 1015.1mbar

The month with the highest atmospheric pressure is December (1019.7mbar).
The month with the lowest atmospheric pressure is July (1011.7mbar).

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Average wind speed in September
Istanbul, Turkey

Average wind speed in September - Istanbul, Turkey
  • Average wind speed in September: 18.1km/h

The windiest month (with the highest average wind speed) is August (20.5km/h).
The calmest month (with the lowest average wind speed) is May (14km/h).

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Average humidity in September
Istanbul, Turkey

Average humidity in September - Istanbul, Turkey
  • Average humidity in September: 68%

The month with the highest relative humidity is February (78%).
The months with the lowest relative humidity are June and July (67%).

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Average rainfall in September
Istanbul, Turkey

Average rainfall in September - Istanbul, Turkey
  • Average rainfall in September: 26mm

The wettest month (with the highest rainfall) is December (52mm).
The driest month (with the least rainfall) is August (11mm).

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Average rainfall days in September
Istanbul, Turkey

Average rainfall days in September - Istanbul, Turkey
  • Average rainfall days in September: 10 days

The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is August (3.8 days).

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Average snowfall in September
Istanbul, Turkey

Average snowfall in September - Istanbul, Turkey
  • Average snowfall in September: 0mm

The month with the highest snowfall is January (24mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

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Average snowfall days in September
Istanbul, Turkey

Average snowfall days in September - Istanbul, Turkey
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (3.7 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).

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Average sea temperature in September
Istanbul, Turkey

Average sea temperature in September - Istanbul, Turkey
  • Average sea temperature in September: 22.8°C

The best month for swimming (with the highest average sea temperature) is August (24.9°C).
The coldest month (with the lowest average sea temperature) is February (7.8°C).

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Average daylight in September /
Average sunshine in September
Istanbul, Turkey

Average daylight in September / Average sunshine in September - Istanbul, Turkey
  • Average daylight in September: 12h and 28min

The month with the longest days is June (Average daylight: 15h and 5min).
The month with the shortest days is December (Average daylight: 9h and 17min).

  • Average sunshine in September: 8h and 54min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 4h and 48min).

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Average sunshine days in September
Istanbul, Turkey

Average sunshine days in September - Istanbul, Turkey
  • Average sunshine days in September: 16.9 days

The month with the most sunshine days is August (25.5 days).
The month with the least sunshine days is February (12.6 days).

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Average UV index in September
Istanbul, Turkey

Average UV index in September - Istanbul, Turkey
  • Average UV index in September: 5

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 2).

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Average cloud cover in September
Istanbul, Turkey

Average cloud cover in September - Istanbul, Turkey
  • Average cloud cover in September: 24

The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and August (Cloud cover 12).

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Average visibility in September
Istanbul, Turkey

Average visibility in September - Istanbul, Turkey
  • Average visibility in September: 10km

The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January and February (9km).

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