On September 4, Bulgaria will experience mostly sunny weather, with cumulus clouds forming in the afternoon. These clouds are expected to bring isolated rain showers and thunderstorms, particularly in the mountainous regions and to the east. Winds will be light to moderate from the northeast. High temperatures will range from 30°C to 35°C, with Sofia seeing around 31°C.

Along the Black Sea coast, the day will start sunny, but the northern areas will become overcast after midday, accompanied by isolated rain showers and thunderstorms. A moderate northeasterly wind will prevail, with highs reaching between 26°C and 29°C. The seawater temperature will range from 25°C to 27°C.

In the mountainous regions, the weather will remain mostly sunny, but skies will partially overcast in the afternoon. Isolated rain showers and thunderstorms are likely in the Rila, Rhodopes, and Balkan mountains. The wind will be moderate from the northeast. High temperatures will be around 22°C at 1,200 meters and approximately 16°C at 2,000 meters.