Weather and climate in Istanbul, Türkiye: monthly averages and best time for stargazing

Best for stargazingAug, Sep, OctMost clear, dark hours

Warmest monthAugustAverage high 29°C

Coolest monthJanuaryAverage low 3°C

Wettest monthDecember82 mm on average

What the weather is like in Istanbul

The warmest month in Istanbul is August, with average highs of 29°C. The coolest is January, when nights average 3°C. About 624 mm of rain and snow falls in a typical year, most in December and least in July.

Skies are clearest in July (28% average cloud cover) and cloudiest in January (76%). Combining cloud with the length of truly dark nights, August, September, October offer the most clear, dark hours for stargazing.

Clear, dark hours per night

2.7 Jan

2.5 Feb

2.9 Mar

2.9 Apr

2.6 May

2.7 Jun

3.7 Jul

4.7 Aug

4.5 Sep

4.0 Oct

3.5 Nov

3.0 Dec

Hours of full astronomical darkness in mid-month, multiplied by the average share of clear sky. A rough guide to how much good observing time a typical night offers.

Monthly averages

Month	High	Low	Precipitation	Cloud cover	Humidity	Wind	Dark hours
January	8°C	3°C	79 mm	76%	83%	15 km/h	11.2 h
February	9°C	4°C	68 mm	75%	82%	16 km/h	10.2 h
March	12°C	5°C	53 mm	67%	79%	15 km/h	9.0 h
April	16°C	9°C	42 mm	61%	76%	13 km/h	7.4 h
May	21°C	14°C	35 mm	55%	74%	12 km/h	5.7 h
June	26°C	19°C	36 mm	42%	69%	12 km/h	4.6 h
July	29°C	21°C	20 mm	28%	66%	15 km/h	5.2 h
August	29°C	22°C	22 mm	30%	66%	17 km/h	6.7 h
September	25°C	19°C	54 mm	46%	68%	15 km/h	8.4 h
October	20°C	14°C	70 mm	59%	76%	15 km/h	9.8 h
November	15°C	10°C	63 mm	68%	80%	14 km/h	10.9 h
December	10°C	6°C	82 mm	74%	82%	15 km/h	11.5 h

Climate averages: NASA POWER, 2001–2025, for the grid area around 41.00, 28.75 (about 50 km across). High and low temperatures are estimated from the monthly mean and the average daily range. Hills, coasts and cities can differ from the area average. Sources and methods.