The Collaborative International Dictionary of English v.0.48:

Mistral \Mis"tral\, n. [F., fr. Proven[,c]al.]
   A violent and cold northwest wind experienced in the
   Mediterranean provinces of France, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mistral
    n 1: a strong north wind that blows in France during the winter

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "mistral":
   Euroclydon, Tehuantepec wind, Tehuantepecer, bise, east wind,
   easter, easterly, gregale, levanter, north wind, northeaster,
   norther, northwester, south wind, southeaster, souther,
   southerly buster, southwester, tramontane, west wind, wester,
   westerly