İstanbul December Weather, Average Temperature (Turkey) (2024)

Daily high temperatures decrease by 3°C, from 12°C to 9°C, rarely falling below 4°C or exceeding 17°C.

Daily low temperatures decrease by 3°C, from 7°C to 5°C, rarely falling below -0°C or exceeding 12°C.

For reference, on 31 July, the hottest day of the year, temperatures in İstanbul typically range from 21°C to 29°C, while on 6 February, the coldest day of the year, they range from 4°C to 9°C.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on December. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Jeju City, South Korea (8,213 kilometres away); Matsue, Japan (8,530 kilometres); and Atami, Japan (8,961 kilometres) are the far-away foreign places with temperatures most similar to İstanbul (view comparison).

© OpenStreetMap contributors

Compare İstanbul to another city:

The month of December in İstanbul experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 57% throughout the month. The highest chance of overcast or mostly cloudy conditions is 58% on 13 December.

The clearest day of the month is 1 December, with clear, mostly clear, or partly cloudy conditions 45% of the time.

For reference, on 13 December, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 58%, while on 25 July, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 96%.

A wet day is one with at least 1 millimetre of liquid or liquid-equivalent precipitation. In İstanbul, the chance of a wet day over the course of December is essentially constant, remaining around 31% throughout.

For reference, the year's highest daily chance of a wet day is 32% on 12 December, and its lowest chance is 7% on 11 July.

Over the course of December in İstanbul, the chance of a day with only rain remains an essentially constant 29% throughout, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 0% throughout.

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during December in İstanbul is gradually decreasing, starting the month at 72 millimetres, when it rarely exceeds 136 millimetres or falls below 21 millimetres, and ending the month at 65 millimetres, when it rarely exceeds 117 millimetres or falls below 17 millimetres.

The highest average 31-day accumulation is 73 millimetres on 8 December.

Over the course of December in İstanbul, the length of the day is essentially constant. The shortest day of the month is 21 December, with 9 hours, 13 minutes of daylight and the longest day is 1 December, with 9 hours, 27 minutes of daylight.

The earliest sunrise of the month in İstanbul is 08:09 on 1 December and the latest sunrise is 19 minutes later at 08:29 on 31 December.

The earliest sunset is 17:35 on 7 December and the latest sunset is 10 minutes later at 17:45 on 31 December.

Daylight saving time is not observed in İstanbul during 2024.

For reference, on 20 June, the longest day of the year, the Sun rises at 05:32 and sets 15 hours, 8 minutes later, at 20:39, while on 21 December, the shortest day of the year, it rises at 08:25 and sets 9 hours, 13 minutes later, at 17:39.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

The figure below presents a compact representation of key lunar data for December 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The chance that a given day will be muggy in İstanbul is essentially constant during December, remaining around 0% throughout.

For reference, on 4 August, the muggiest day of the year, there are muggy conditions 48% of the time, while on 19 November, the least muggy day of the year, there are muggy conditions 0% of the time.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 metres above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in İstanbul is essentially constant during December, remaining within 0.3 kilometres per hour of 18.4 kilometres per hour throughout.

For reference, on 4 February, the windiest day of the year, the daily average wind speed is 19.2 kilometres per hour, while on 30 May, the calmest day of the year, the daily average wind speed is 13.8 kilometres per hour.

The hourly average wind direction in İstanbul throughout December is predominantly from the north, with a peak proportion of 33% on 22 December.

İstanbul is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in İstanbul is decreasing during December, falling by 3°C, from 13°C to 10°C, over the course of the month.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 0°C) in the year (the calendar year in the Northern Hemisphere, or from 1 July until 30 June in the Southern Hemisphere).

The growing season in İstanbul typically lasts for 10 months (303 days), from around 24 February to around 23 December, rarely starting after 20 March, or ending before 30 November.

During December in İstanbul, the chance that a given day is within the growing season is very rapidly decreasing falling from 89% to 31% over the course of the month.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 10°C and a cap of 30°C.

The average accumulated growing degree days in İstanbul are gradually increasing during December, increasing by 28°C, from 2,254°C to 2,282°C, over the course of the month.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy in İstanbul is essentially constant during December, remaining within 0.1 kWh of 1.7 kWh throughout.

The lowest average daily incident shortwave solar energy during December is 1.5 kWh on 23 December.

For the purposes of this report, the geographical coordinates of İstanbul are 41.014 deg latitude, 28.950 deg longitude, and 39 m elevation.

The topography within 3 kilometres of İstanbul contains only modest variations in elevation, with a maximum elevation change of 98 metres and an average elevation above sea level of 28 metres. Within 16 kilometres contains only modest variations in elevation (284 metres). Within 80 kilometres contains very significant variations in elevation (1,311 metres).

The area within 3 kilometres of İstanbul is covered by artificial surfaces (69%) and water (22%), within 16 kilometres by artificial surfaces (47%) and water (36%), and within 80 kilometres by water (58%) and trees (22%).

This report illustrates the typical weather in İstanbul, based on a statistical analysis of historical hourly weather reports and model reconstructions from 1 January 1980 to 31 December 2016.

Temperature and Dew Point

There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in İstanbul.

For each station, the records are corrected for the elevation difference between that station and İstanbul according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at İstanbul is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between İstanbul and a given station.

The stations contributing to this reconstruction are:

• Istanbul Atatürk Airport (LTBA, 83%, 12 km, west, 10 m elevation change)
• Sabiha Gökçen International Airport (LTFJ, 17%, 33 km, southeast, 56 m elevation change)

To get a sense of how much these sources agree with each other, you can view a comparison of İstanbul and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

Please review our full terms contained on our Terms of Service page.