A mold used in continuous steel casting includes a plurality of mold copper plates. At least one of the plurality of mold copper plates has an optical fiber temperature sensor embedded therein across a width direction of the mold copper plate at at least two different levels in a casting direction.

The present invention relates to a method and a system for determining a temperature value of a molten metal bath. The method according to the invention has been proven to be especially suitable for installations of metallurgical vessels which are constantly moved during the metal making process.