September weather forecast
Istanbul, Turkey

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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

September brings the early whispers of autumn to Istanbul while retaining the warmth of summer. The temperatures, while decreasing compared to peak summer, still remain in a comfortable range for outdoor activities. A marked increase in rainfall compared to the summer months begins to usher in autumnal freshness. September in Istanbul embodies an enticing blend of summer's warmth and autumn's charm, with landscapes beginning to wear hues of fall. The late-summer sea temperatures remain ideal for water activities, while slightly cooler evenings make alfresco dining particularly enjoyable.

Temperature

The shift from August to September in Istanbul includes a small decrease in the average high-temperature, from 27.8°C (82°F) to a still moderately hot 24.3°C (75.7°F). During the September nights, Istanbul's temperature maintains an average close to the daytime highs, settling at a pleasant 20.4°C (68.7°F).

Humidity

In Istanbul, the average relative humidity in September is 68%.

Rainfall

In Istanbul, Turkey, in September, during 10 rainfall days, 26mm (1.02") of precipitation is typically accumulated. Throughout the year, in Istanbul, there are 130.7 rainfall days, and 400mm (15.75") of precipitation is accumulated.

Snowfall

April through November are months without snowfall in Istanbul.

Sea temperature

In Istanbul, in September, the average water temperature is 22.8°C (73°F).
Note: Given an individual's cold sensitivity, considering factors like sunshine, wind, and air temperature, a brief swim in 22.8°C (73°F) water might be pleasurable. (FYI: The standard water temperature for Olympic swimming contests is 25°C (77°F) to 28°C (82.4°F).)

Daylight

The average length of the day in September is 12h and 28min.
On the first day of the month, sunrise is at 06:31 and sunset at 19:36. On the last day of September, in Istanbul, sunrise is at 07:00 and sunset at 18:47 +03.

Sunshine

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

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, the maximum UV index of 5 suggests these recommendations:
Guard yourself - An obligation to protect skin and eyes from harm exists. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Stay sun-safe with clothing that is both closely woven and worn loosely. Heads up! Sand and water reflection magnifies the UV exposure from the Sun.
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Frequently asked questions

What is the temperature in September in Istanbul?

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

What is the average humidity in September in Istanbul?

In Istanbul, Turkey, the average relative humidity in September is 68%.

How much does it rain in Istanbul in September?

In Istanbul, Turkey, during September, the rain falls for 10 days and regularly aggregates up to 26mm (1.02") of precipitation.

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 in Istanbul is 22.8°C (73°F). Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 22.8°C (73°F) water may be enjoyable.

How many hours of daylight does Istanbul have in September?

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

What time are sunrise and sunset in September in Istanbul?

In September, on the first day of the month, sunrise is at 06:31 and sunset at 19:36. On the last day of the month, in Istanbul, Turkey, sunrise is at 07:00 and sunset at 18:47 +03.

How many hours of sunshine does Istanbul have in September?

The average sunshine duration in September in Istanbul is 8.9h.

How high is the UV index 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 medium hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover

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 3min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in September: 8h and 5min

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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Istanbul, Turkey

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