The weather is changing again in Istanbul. The weather forecast report of the Istanbul Metropolitan Municipality Disaster Affairs and Risk Management Department dated Sunday, September 27, 2026, revealed the details of the rainy weather that is expected to be effective in the city in the new week. According to AKOM's assessment, successive cool and rainy weather systems coming from the Balkans will be effective throughout the Marmara Region, especially in Istanbul. With these systems, the wind is expected to blow from the north in the form of a storm from time to time, and the temperatures are expected to drop below 20 degrees.
MONDAY WILL START WITH SHOWERS
AKOM's weekly forecast predicts thunderstorms and rainy weather for Istanbul on Monday, September 28. While temperatures are expected to be between 16-20 degrees, the amount of precipitation is estimated to be between 20-50 kilograms/square meter.
The daily forecast prepared for Monday shows the temperature as 19 degrees in the morning, 22 degrees at noon, 20 degrees in the evening and 17 degrees at night.
While the humidity rate is expected to be between 55-90 percent, the wind is expected to blow harshly from the north-east, gale-like at intervals, and its speed is expected to reach 30-60 kilometers per hour.
ATTENTION TO TUESDAY
One of the most remarkable weather forecasts of the week came for Tuesday, September 29th. AKOM expects thunderstorms in Istanbul on Tuesday. It is estimated that temperatures will be between 14-18 degrees and the amount of precipitation will be between 30-60 kilograms/square meter. Thus, on the second day of the new week, both temperatures are expected to decrease and the amount of precipitation is expected to increase.
IT CONTINUES TO RAIN ON WEDNESDAY
On Wednesday, September 30, the weather in Istanbul will be very cloudy and rainy. While temperatures were expected to be between 13-19 degrees, the amount of precipitation was estimated as 10-20 kilograms/square meter. After the rain, there is a limited increase in temperatures.
RAIN IS NOT EXPECTED ON THURSDAY
On Thursday, October 1, the weather in Istanbul will be partly and very cloudy. While temperatures are expected to remain between 12-20 degrees, AKOM's forecast stated that no rain is expected for this day. But the rainy weather is not completely left behind.
THERE IS RAIN AGAIN ON FRIDAY AND THE WEEKEND
Very cloudy, slightly rainy weather is expected in Istanbul on Friday, October 2. It is estimated that temperatures will be between 12-19 degrees and the amount of precipitation will be between 3-7 kilograms per square meter. On Saturday, October 3, thunderstorms will be effective again. Temperatures are expected to be between 13-20 degrees and the amount of precipitation is expected to be between 5-15 kilograms/square meter.
Weather of the week in Istanbul;
Monday, September 28: Thunderstorm — 16-20°C — 20-50 kg/m²
Tuesday, September 29: Thunderstorm — 14-18°C — 30-60 kg/m²
Wednesday, September 30: Mostly cloudy, showers — 13-19°C — 10-20 kg/m²
Thursday, October 1: Partly cloudy — 12-20°C — No precipitation expected
Friday, October 2: Mostly cloudy, light rain — 12-19°C — 3-7 kg/m²
Saturday, October 3: Thunderstorm — 13-20°C — 5-15 kg/m²
While heavy rain and strong winds stand out in the first two days of the new week in Istanbul, temperatures are expected to drop below 20 degrees.
