Cyclone Boris to end Croatia’s summer with 15°C drop in temperatures

Zagreb

Although summer is still officially here and Croatia has experienced a scorching hot season, a sudden change in weather is on the horizon.

Cyclone Boris is set to bring a dramatic drop in temperatures, along with heavy rain and storms, marking an abrupt shift from the summer heat.

The Croatian Meteorological and Hydrological Service (DHMZ) has issued warnings for potentially dangerous weather over the coming days, with heavy rain, thunderstorms, and strong winds forecast as the country prepares for a significant cooldown.

From Thursday, 12 September, cold air from the Atlantic will move from Iceland towards the Adriatic, forming Cyclone Boris, which will pass over the region on Friday, DHMZ said.

Alongside this, a circulation of cold, moist air is expected to linger for several days, bringing substantial rainfall and a noticeable drop in temperatures across the country.

From mid to late 20s to cooler temperatures

The DHMZ predicts cloudy conditions with rain across the mainland, with temperatures falling to around 10°C.

The heaviest rainfall is expected along the Adriatic coast, where up to 100 mm of rain could fall in two days. Thunderstorms, short downpours, and possible hail are also forecast for coastal areas.

Rivers such as the Drava, Mura, and Danube could experience rising water levels, as their flow is influenced by rainfall in upstream countries. Some rivers may reach flood warning levels, depending on the amount of rain received in Austria, Slovenia, and other nearby nations.

Warning in place

The European Flood Awareness System (EFAS) and DHMZ models indicate the potential for high water in these rivers over the coming days.

On Thursday, the Adriatic will experience strong to stormy winds, with a shift to a strong northern wind by Friday as the cyclone moves southeast. Urban and flash flooding is possible, particularly in the west (Istria) and along the Adriatic coast and hinterlands.

Warnings have been issued for dangerous weather, with yellow and orange alerts for heavy rain, thunderstorms, and storm-force winds starting from Thursday.