Calan Mai ( 'first day of May') or Calan Haf ( 'first day of Summer'), also historically called Cyntefin, is the Welsh celebration of May Day (1 May). It marks the beginning of summer and traditionally it involved festivities around bonfires, maypoles, and carol singing. Some of its traditions parallel the Gaelic May Day festival Beltane, and other May Day and Walpurgis Night traditions in Europe.

Customs

Traditionally, bonfires (coelcerth) were lit at Calan Mai in parts of Wales. They were lit in Glamorgan until the 1830s. Nine men would gather branches of nine different trees, remove all metal, then light the fire by friction between wood. A fire kindled in such a way is known as a need-fire. Sometimes two fires were built side-by-side. Round cakes of oatmeal and brown-meal were sliced and placed in a bag, and participants each chose one; those who chose a brown-meal slice had to leap three times over flames, or run thrice between the bonfires. This was believed to ensure a good harvest. Calan Mai bonfires were also recorded in Montgomeryshire. The Scottish Highlands had very similar May Day (Beltane) bonfire customs, and historian Ronald Hutton suggests they were all survivals of a tradition that was once more widespread. Maypoles were traditionally set up for Calan Mai. In Britain, the maypole was found primarily in areas of English influence. However, the earliest account is from a Welsh poem by Gryffydd ap Adda ap Dafydd in the mid-14th century, in which he described people making festivities around a tall birch pole at Llanidloes in Montgomeryshire. Small groups of young men went about singing May carols (carolau Mai) or summer carols (carolau haf) at Calan Mai, and were rewarded with food and drink. Other traditions: