climate

CLIMATE

Although the topography of the region at first sight looks flat, it is actually quite diverse. The Vipava Valley is surrounded by hills from three sides: the Trnovo Plateau, The Nanos Plateau, the Hrušica Plateau and the Vipava Hills. Due to the open land to the west, the region is under great influence of the Mediterranean climate. Therefore, the vegetational period lasts two months longer than in the central Slovenia. High plateaus conjoin various different climates, Alpine, Continental and even Mediterranean, which is reflected in the diversity of flora and fauna, some species are endemic to this region only.

Mild winters and hot summers are typical of the valley. Mean July temperature, measured in Ajdovščina, is 24°C and mean winter temperature is 4°C. The average annual rainfall in the Vipava Valley amounts to 1,500 mm (59.0551 inches).

The climate in the Vipava Valley is constantly influenced by winds – the warm and humid southwester wind and the Bora. The southwester wind blows from Africa to Italy and on the Adriatic Coast. It rises when the atmospheric pressure is high over Africa and low over Europe. First it blows from Africa as a warm dry wind, which brings desert dust, but after passing the sea it gets humid, on its way it stirs the sea and brings bad weather.

THE BORA is distinctive of the Vipava Valley. It is a cold gusty wind, which blows down from the plateau to the valley. The average speed of the wind is 80 kph, but in the winter the speed can reach up to 180 kph. The Bora affects social and cultural relations in the valley. Even the Roman poet Claudianus mentioned the Bora in one of his poems. In 394 AD Theodosius fought a fierce and bloody battle against the forces of the usurper Eugenius at the River Frigidus. However, Claudianus, inspired by the great victory of Theodosius, ascribed the victory to the impetuous Bora, which redirected arrows and defeated the enemy.