In former times in Europe, Indian summer was called Saint Martin's Summer, referring to St. Martin's day, November 11, when it was supposed to end. In British English "St. Martin's Summer" was the most widely used term until the American phrase Indian Summer became better known in the 20th century.

In Italy, St Martin's summer (Estate di San Martino) was expected and celebrated as a rural tradition with ancient origins, and is marked by a festival throughout the peninsula on November 11.

In Spain, it is called Veranillo de San Miguel or Veranillo de San Martín, depending on which date it occurs. It can also be called Veranillo del Membrillo.

In Russia, it is called Women's Summer / Babye Leto (Бабье лето).

In Galicia (northern Spain), it is called Veraniño de San Martiño, and in Portugal it is called "Verão de São Martinho," both of which refer to St. Martin's summer. In both cases, it is celebrated in rural areas with Magostos (Magusto in Portuguese, from Magnus Ustus, Big Fire in reference to the magical nature of fire), a celebration of Celtic origins in which bonfires, roasted chestnuts and wine have an important role.

In Sweden it is called "brittsommar", which is derived from Birgitta and Britta, who have their "name day" in the Swedish calendar on October 7. That is when Britt Mass, an official fall open-air market, was held.

In Germany and Austria it is called "Altweibersommer" (Old Ladies Summer) because the many white spider silks seen at this time of the year were have been associated with the norns of Norse folklore.

An alternative to St Martin's summer was "Saint Luke's summer", as the saint's feast day is October 18. Another alternative was "All-hallown summer", as Halloween is October 31; the expression is used in Shakespeare's King Henry IV, Part 1, Act 1 Scene 2.