Climate averages 1991–2020
Istanbul weather
in December.
A cool, wet month: the 10th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cool month in Istanbul: daytime highs average 10.1°C and nights cool to about 6.4°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 99 mm of rain on roughly 13 days, which makes December a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 9 h 17 min on an average December day.
The nearest other city in this atlas is Üsküdar (5 km away). In December its highs average 10.1°C, about as warm as Istanbul, with 99 mm of rain.
Among the 138 cities listed in Turkey, Istanbul ranks joint 60th of 138 for the warmest December highs and joint 87th of 138 for the driest December (rainfall, lowest first). The mean December high of those 138 cities is 9.3°C; Istanbul is 0.8°C warmer than that mean.
From December to January, average highs fall by 1.9°C to 8.2°C, and monthly rainfall falls from 99 mm to 85 mm.
The annual picture
December in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Istanbul climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.2°C4.2°C | 4.2°C | 85 | 12.4 | 9.610 h |
| February | 8.7°C4.1°C | 4.1°C | 70 | 11.7 | 10.611 h |
| March | 10.8°C5.6°C | 5.6°C | 72 | 10.6 | 11.912 h |
| April | 14.9°C8.8°C | 8.8°C | 47 | 8.1 | 13.313 h |
| May | 19.8°C13.6°C | 13.6°C | 35 | 6.1 | 14.514 h |
| June | 24.7°C18.4°C | 18.4°C | 32 | 5.4 | 15.115 h |
| July | 27.5°C21.1°C | 21.1°C | 23 | 3.4 | 14.815 h |
| August | 27.8°C21.8°C | 21.8°C | 20 | 3.2 | 13.814 h |
| September | 23.9°C18.5°C | 18.5°C | 46 | 6.4 | 12.513 h |
| October | 19.1°C14.5°C | 14.5°C | 75 | 9.0 | 11.111 h |
| November | 14.3°C10.1°C | 10.1°C | 72 | 9.6 | 9.910 h |
| December, selected | 10.1°C6.4°C | 6.4°C | 99 | 12.8 | 9.39 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Üsküdar in DecemberTurkey · 5 kmHigh 10.1°C · Low 6.1°C · 99 mm rain
- Şişli in DecemberTurkey · 6 kmHigh 9.8°C · Low 5.6°C · 99 mm rain
- Sultangazi in DecemberTurkey · 12 kmHigh 9.6°C · Low 5.3°C · 84 mm rain
- Ümraniye in DecemberTurkey · 15 kmHigh 9.6°C · Low 5.7°C · 99 mm rain
- Küçükçekmece in DecemberTurkey · 15 kmHigh 9.9°C · Low 6.3°C · 84 mm rain
- Başakşehir in DecemberTurkey · 17 kmHigh 9.5°C · Low 5.5°C · 84 mm rain
- Esenyurt in DecemberTurkey · 23 kmHigh 9.6°C · Low 6.2°C · 84 mm rain
- Sancaktepe in DecemberTurkey · 24 kmHigh 9.8°C · Low 5.8°C · 100 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Istanbul) is explained once on the Istanbul year overview and on the Sources, method and limits page.
Ümraniye, Üsküdar and Şişli lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.