Istanbul records about 816mm of rain across roughly 123 wet days a year, which is a 34% chance on an average day. December is the wettest month at 119mm (15% of the annual total) and July the driest at 18mm. Local rain type: steady rain. Essential from October through March. Summer is reliably dry, making it perfect for walking the historic peninsula. Winter rain can be persistent and chilly.
Chance of rain on an average day: 34%
Rainfall climatology for Istanbul. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 816mm |
| Rain days per year | 123 |
| Odds on an average day | 34% |
| Wettest month | December — 119mm over 21 days |
| Driest month | July — 18mm over 3 days |
| Rain type | steady rain |
| Best dry window | June through August provides warm, dry Mediterranean conditions. |
| Worst rain window | November through January brings cold rain and occasional snow flurries. |
December delivers 561% more rain than July (119mm vs 18mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 15% of the annual total, so rain in Istanbul is spread through the year — there is no season you can rely on being dry.
Istanbul rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 21 days in December against 3 in July — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 99mm | 17 | 57% | 9°C |
| February | 72mm | 13 | 43% | 9°C |
| March | 70mm | 12 | 40% | 12°C |
| April | 46mm | 8 | 27% | 16°C |
| May | 31mm | 5 | 17% | 22°C |
| June | 23mm | 4 | 13% | 26°C |
| July | 18mm | 3 | 10% | 29°C |
| August | 18mm | 3 | 10% | 29°C |
| September | 42mm | 7 | 23% | 26°C |
| October | 66mm | 12 | 40% | 22°C |
| November | 101mm | 18 | 60% | 16°C |
| December | 119mm | 21 | 70% | 12°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Istanbul we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Istanbul records rain on roughly 123 days a year — about a 34% chance on any given day — totalling around 816mm.
December, with about 119mm over 21 rain days. That is 15% of the entire year's rainfall in a single month.
July is the driest month at 18mm across roughly 3 days. June through August provides warm, dry Mediterranean conditions.
Essential from October through March. Summer is reliably dry, making it perfect for walking the historic peninsula. Winter rain can be persistent and chilly.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.