Istanbul in October is mild and golden early in the month, then wetter and darker by the end. Average highs fall to 20.6°C (69°F), rainy days rise to about 9.5, and the sea still averages 18.8°C (66°F). Two big dates shape it: the Turkish Grand Prix on 1 to 3 October 2027, and Republic Day on 29 October.
Checked on 10 November 2026. Climate: MGM, 1950–2025. Sea: MGM Marmara sea report. Visitors: the provincial tourism directorate. The F1 dates come from Time Out Türkiye’s report of the calendar, and the daylight hours are our own 2027 figures.
Istanbul in October: weather, sea and daylight
| Long-term average | October |
|---|---|
| Daytime high | 20.6°C (69°F) |
| Night low | 13.7°C (57°F) |
| Rainy days | 9.5 |
| Monthly rain | 66.3 mm |
| Warmest day on record | 33.5°C (92°F) |
| Coldest day on record | 2.5°C (36°F) |
| Sea of Marmara, average water temperature | 18.8°C (66°F) |
The water figure is the 1970–2025 monthly average for the whole Sea of Marmara, not for the Bosphorus or the Black Sea beaches, so a local beach can feel colder.
On 1 October 2027 the sun rises near 06:59 and sets near 18:48. By 15 October it sets near 18:25, and daylight lasts 11h11m. Plan outdoor sights for the morning and early afternoon.
Istanbul in October: daylight through the month
| 2027 | Sunrise | Sunset | Daylight |
|---|---|---|---|
| 1 Oct | 06:59 | 18:48 | 11h49m |
| 15 Oct | 07:14 | 18:25 | 11h11m |
| 31 Oct | 07:33 | 18:03 | 10h30m |
October loses about 1 hour 19 minutes of light, and the sun sets near 18:00 by the end of the month. Türkiye does not change its clocks, so the early dusk is not a clock effect.
October compared with September
| Long-term average | September | October |
|---|---|---|
| Daytime high | 25.9°C | 20.6°C |
| Rainy days | 5.5 | 9.5 |
| Monthly rain | 39.7 mm | 66.3 mm |
| Sea of Marmara | 22.3°C | 18.8°C |
The average high drops by 5.3°C, and monthly rain rises by about two thirds. October is the month the weather turns, so check the forecast before you commit to an outdoor day.
Turkish Grand Prix weekend: 1 to 3 October 2027
Formula 1 returns to Istanbul Park, with the race on Sunday 3 October. Hotels near the circuit and across the city may fill up. Read our Turkish Grand Prix guide for where to stay and how to plan the trip.
Republic Day on 29 October
29 October is Republic Day, a public holiday that celebrates the founding of the Republic in 1923. The afternoon of 28 October is usually a half-day. In 2027 it falls on a Friday, so the holiday forms a long weekend. See our Republic Day guide for what happens in the city.
How busy is Istanbul in October?
| Foreign visitors to Istanbul | Number |
|---|---|
| October 2024 | 1,745,808 |
| October 2025 | 1,857,314 (+6.4% on 2024) |
October 2025 matched August’s visitor count, which makes it one of the busiest months of the year, even though the weather cools. The record is useful when you plan: book early.
What to do in Istanbul in October
- Take a ferry on a clear day for autumn light on the Bosphorus.
- Save indoor sights for rainy afternoons. Our rainy day plan helps.
- Visit Topkapı Palace and Gülhane on a dry morning. Topkapı closes on Tuesdays.
Per day, the official count gives about 59,910 foreign arrivals in October 2025, matching August 2025 at about 59,770. It is our own division of the monthly counts.
Two October weekends to plan around
- 1 to 3 October 2027: the Grand Prix weekend. The race is on Sunday 3 October, so plan for the whole weekend, not one night. See our Grand Prix guide.
- 29 October 2027: Republic Day falls on a Friday, so the holiday forms a long weekend. Ferries and hotels may be busy. See our Republic Day guide for how the day looks in the city.
Packing list for an October trip
- A waterproof jacket with a hood.
- Layers that handle warm afternoons and cool nights.
- Closed shoes with grip on wet stone.
- A compact umbrella.
Should you visit Istanbul in October?
Yes, especially early in the month, though it is busy. Next comes Istanbul in November. Our weather table compares every month.
October questions answered
Is October wet?
It averages about 9.5 rainy days, more than September.
Can you still swim?
The sea averages 18.8°C, which most people find cold.
