When did Jewish men have to pay the temple tax?

Each year, every adult male Israelite gave an obligatory donation of one-half shekel to the Tabernacle (Exodus ch.30); and later, to the Temple (Mishna, tractate Shekalim). This money was customarily given during Adar (early Spring). It paid for the sacrifices, Temple upkeep, and related costs.

The purchasing power in those days of 1/2 shekel was enough to support a small family for about four days.