Tin fortune-telling is the Finnish New Year's Eve tradition of melting a small piece of metal and interpreting its resulting shape.
In the custom, a small piece of metal is heated until it melts and then poured into cold water. The rapidly hardened shape is examined, sometimes by holding its shadow against a light, and interpreted as a prediction for the coming year.
The Finnish practice is commonly known as uudenvuodentina, literally “New Year's tin.” Traditional pieces were sold specifically for the ritual, and their shapes could suggest themes such as travel, money, or romance depending on the interpreter's imagination.
The custom has also existed elsewhere in northern Europe, but Finland made it a familiar part of New Year's celebrations. Modern safety and environmental concerns have led to restrictions or changes involving lead-containing metals, so contemporary versions may use safer materials.