Travel time: Year-round
Český Krumlov features a humid continental climate, characterized by four distinct seasons with significant temperature shifts. Nestled in the valley of the Vltava River and surrounded by the foothills of the Blanský Forest, the town’s weather is deeply influenced by its topography. The river acts as a thermal regulator, cooling the medieval streets during summer heatwaves and contributing to early morning mists that shroud the castle in autumn.
Spring is a period of rapid transition. March can still feel wintry, with occasional snow and temperatures hovering around 8°C (46°F). By May, the landscape transforms as the hillsides turn green and average highs reach a pleasant 17°C to 19°C (63°F–66°F). This season is unpredictable; locals often prepare for "April weather," which can cycle from bright sunshine to hail within an hour.
Summers are warm but rarely oppressive. Daytime highs typically range between 22°C and 25°C (72°F–77°F), though occasional spikes can reach 30°C (86°F). June is statistically the wettest month, often seeing brief but intense afternoon thunderstorms. The Vltava River becomes the center of life during these months, as the water temperature remains cool, providing a natural air-conditioning effect for the riverside cafes.
September offers a "second spring" with crisp air and clear skies, often referred to as Babí léto (Old Ladies' Summer). Highs average 19°C (66°F) in September but fall sharply to 8°C (46°F) by November. This is the driest time of year. As the days shorten, the river valley frequently traps pockets of cool air, leading to dense, atmospheric morning fogs that clear by midday.
Winters are cold and atmospheric, with January being the hallmark month for freezing conditions. Temperatures frequently dip below 0°C (32°F) at night and rarely rise above 3°C (37°F) during the day. Snow is common, often blanketing the red-tiled roofs and cobblestones, though it rarely accumulates to extreme depths due to the town's lower elevation relative to the nearby Bohemian Forest mountains.
Because of the high humidity (averaging 75–85% in winter), the cold in Český Krumlov often feels "damp" and penetrates deeper than dry mountain air. Conversely, the summer heat feels "fresh" due to the abundance of greenery and the constant movement of the river.