The Autan is a south-easterly, föhn-type wind deriving from the Mediterranean and blowing across the Languedoc into the Tarn and Garonne valleys affecting the Lauragais and the Toulouse area. It has a more southerly component in the Cantal region.
The Autan is caused by high pressure moving NE from the Azores or the Eastern Mediterranean to the Baltic. Starting as a damp maritime wind, the Autan is blowing over the Languedoc into the Aquitaine, channelled and intensified by narrowing of lowlands between the Montagne Noir and Pyrenees and undergoes sudden acceleration between Corbieres and the south of the Massif Central.
The wind has distinct föhn characteristics when descending in the west and may easily reach gale force. The gustiness is enhanced along the steep and narrow valleys of the River Aude and Thauré, north of the Pyrenees and the Montagne Noir. Gusts can exceed twice mean speed, possibly enhanced by lee-wave activity. The effects on humans is similar to the föhn: a warm and close wind, sweltering and oppressive, causing headaches and general indisposition.
The name is also applied to other winds in SE Aquitane that may or may not be related to the Autan, such as the L'autan blanc (white Autan), described as of continental origin, bringing heat in summer and cold in winter, and l'autan noir (black Autan), a warm wind, precursor of intermittent rain and being less frequent than the 'white Autan'.