Türkiye's State Meteorological Service (MGM) has issued three official warnings relevant to road and sea travel on Friday, 28 August 2026. The broad rain notice covers ten provinces until midnight, while marine-storm conditions of 50–75 km/h are expected in two sea areas. MGM later issued a separate Istanbul-specific strong-rain warning for 03:40–07:00; that window has ended and should not be presented as a current all-day warning. In a separate binding local measure, Giresun Governorate has banned swimming at every beach in the province for the whole of 28 August.
Morning rain zone
From Friday morning, intermittent and locally heavy showers and thunderstorms are forecast around Kocaeli, Sakarya, Düzce, Zonguldak and Bartın. MGM gives the rain-warning window as 06:00–23:59 on 28 August. Conditions can vary within each province, so the notice should not be read as continuous rain everywhere for eighteen hours.
Areas added from midday
From around midday, the warning also covers Bolu, Karabük, Kastamonu, Sinop and Çorum. MGM lists possible flash flooding, waterlogging, landslides, lightning, local hail, strong gusts during rain and transport disruption. Drivers should check the precise route and avoid treating a province-wide label as a road-by-road forecast.
The separate Istanbul rain warning has ended
MGM warning No. 443 covered locally strong showers and thunderstorms in Istanbul from 03:40 to 07:00 on 28 August. It was distinct from warning No. 441's ten-province list and its stated period has now expired. Istanbul is still named in the separate western Black Sea marine warning, so travellers should distinguish an ended city rain window from the later sea-area wind risk.
Marine storm near Istanbul and Kırklareli
In the western part of the western Black Sea, between Kırklareli and Istanbul, north to north-easterly winds of force 6–8, approximately 50–75 km/h, are forecast after Friday evening. MGM expects this part of the storm to weaken in the first hours of Saturday, 29 August. This is a sea-area warning; it does not by itself predict the same wind speed in every Istanbul district.
Southern Aegean timing is different
In the southern Aegean, force 6–8 north to north-westerly winds are expected first in the southern sector on Friday evening and more widely from Saturday morning. The warning is scheduled to end after Saturday evening, with the official overall marine window running from 18:00 on 28 August to 23:59 on 29 August.
Giresun bans swimming at every beach on 28 August
Giresun Governorate announced that swimming is prohibited at all beaches and along the entire provincial coast on Friday, 28 August. The restriction is based on expected adverse sea conditions and applies province-wide for the day. It is a local safety order, not a nationwide beach closure; travellers elsewhere should follow the governorate, municipality, lifeguard and coastguard notices for their exact location.
What travellers should verify
MGM warns of possible transport disruption, but it does not announce a blanket cancellation of ferries, flights or buses. Check the operating company before departure, allow extra time on exposed roads and do not enter flooded underpasses or attempt to cross moving water. Boat trips and coastal activities should be confirmed directly with the operator and local authorities.
Turkey Compass assessment
Confirmed: the broad rain warning covers ten provinces, a separate Istanbul rain warning ran only from 03:40 to 07:00, and two marine sectors have their own wind periods. Misleading: saying all of Istanbul or all of Türkiye faces the same storm throughout the day. Geography and timing differ, and live operator information remains necessary for individual journeys.