Verdict: Excellent month
Istanbul Weather in September
September hits the sweet spot in Istanbul — highs around 26°C (79°F), ideal for a full day on foot. Rain is occasional — about 7 wet days in a typical year. Overall, September is one of the best months of the year to be in Istanbul.
Average high
26°C / 79°F
Average low
18°C / 64°F
Rain days
~7
Precipitation
47 mm
What to pack for Istanbul in September
- Summer clothes, plus one light layer for air-con and evenings
- A packable rain shell or compact umbrella earns its space
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in Istanbul: Aug (30°C / 86°F) · Coolest: Jan (10°C / 50°F) · Wettest: Mar (~13 rain days)
10°
4°
Jan
11°
4°
Feb
12°
5°
Mar
17°
9°
Apr
21°
12°
May
26°
18°
Jun
29°
21°
Jul
30°
21°
Aug
26°
18°
Sep
21°
14°
Oct
16°
10°
Nov
13°
7°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)