The best time to visit Istanbul is May, June, September and October, when average highs sit in the comfortable low-to-mid 20s and rain stays light. May climbs to a 21.3 °C average high with 9 rain days, while September holds 25.5 °C with just 7 rain days — ideal for touring the Hagia Sophia without extreme heat. July and August are peak season, hot and packed with school-holiday crowds. Winter is the quiet low season, cool and grey with frequent rain.
Best months MayJuneSeptemberOctober
Istanbul month by month
Average highs and lows (°C), 2016–2025. Highlighted bars are the best months.
| Month | High | Low | Rain days | Sun / day |
|---|---|---|---|---|
| January | 9.3 °C | 3.8 °C | 13 | 5.5 h |
| February | 10.4 °C | 4.3 °C | 11 | 6.8 h |
| March | 12.8 °C | 5.6 °C | 11 | 7.9 h |
| April | 17 °C | 8.6 °C | 9 | 10.1 h |
| May | 21.3 °C | 13.1 °C | 9 | 11.7 h |
| June | 26.5 °C | 18.3 °C | 8 | 13 h |
| July | 29.2 °C | 20.8 °C | 5 | 13.5 h |
| August | 29.2 °C | 21.5 °C | 3 | 12.6 h |
| September | 25.5 °C | 18 °C | 7 | 10.9 h |
| October | 20.2 °C | 13.6 °C | 7 | 8.5 h |
| November | 16.2 °C | 10.2 °C | 9 | 7 h |
| December | 11.6 °C | 6.4 °C | 13 | 5.4 h |
How the months are picked.A month qualifies when its average high sits in the comfortable 20–28 °C band (scored down towards 9 °C and 37 °C), rain days are few and sunshine hours are high — at least 78 % of the city's best-scoring month. July and August are then set aside as peak season (school-holiday crowds and prices) whenever at least three other months qualify; where summer is the only comfortable window they stay. Figures are ten-year averages (2016-01-01 to 2025-12-31) from ERA5 reanalysis data via Open-Meteo (CC BY 4.0) for the city centre coordinates.
When to go, and what to expect
Spring (Mar–May)
May is prime — mild, bright and comfortable for long days of sightseeing.
Summer (Jun–Aug)
June is lovely; July and August suit sun-seekers who can handle heat and crowds.
Autumn (Sep–Nov)
September and October are excellent — warm sea, soft light and thinner crowds.
Winter (Dec–Feb)
For budget travellers and those who love atmospheric, uncrowded museums.
Notable events
- April
- Istanbul Tulip Festival
- June
- Istanbul Music Festival
- Autumn, in odd-numbered years
- Istanbul Biennial (art)
- 29 October
- Republic Day
Frequently asked
Is Istanbul too hot in August?
It is hot — August averages a 29.2 °C high with lows around 21.5 °C, though only 3 rain days and 12.6 hours of sunshine. Manageable if you pace yourself, but the crowds make May, June, September or October easier.
What is the rainiest month?
January and December are wettest, each with 13 rain days and the least sun at around 5.4–5.5 hours a day. Autumn months like September and October see only 7 rain days.
Is winter worth it?
It can be, if you don't mind cool, damp days — January highs reach just 9.3 °C with 13 rain days. You'll trade weather for quiet sites and the lowest crowds of the year.
Know when to go? Now decide where to stay — our Istanbul area guide →
Areas of Istanbul
Best time to visit near here
Sources
- Open-Meteo historical weather API — monthly climate normals, 2016–2025 (CC BY 4.0)
- ERA5 reanalysis (ECMWF / Copernicus) — the underlying temperature, precipitation and sunshine data
- ReasonStay methodology — how the best months are computed and checked
An independent guide to Istanbul — honest, verified, no invented data. Climate figures: ERA5 via Open-Meteo, 2016–2025 averages; the best months are computed from them, not opinion.