Women in Judaism: Dress
Halacha regarding modesty and community customs dictate the dresscode for women. This "code" is practiced primarily byOrthodox Jews. Typically, women are expected to wear sleeves extendingat least to the elbow, blouses or dresses with necklines thatdo not expose any cleavage and skirts long enough to cover theknees when seated.
Pants or slacks may be allowed in certain instances. For example,in many religious kibbutzim the women wear pants out of habit,for the simple reason that they work in agricultural areas orperform other activities where a skirt would be less modest. Thisis the exception; however, when not performing these activities,skirts are worn.
In addition, it is considered a breach of modesty for a marriedwoman to have uncovered hair while in the presence of men otherthan her husband. Customs differ as to how much hair can be showingbeneath the head covering, or if a wig is better or worse thana hat of some sort.
Unmarried women are not required to cover their hair, althoughthere are Sephardic customs that even unmarried women should "puttheir hair up," so that it's not flying "wildly."
Source: Shamash: http://shamash.org/trb/judaism.html