Any day, Worldwide
In many different traditions lighting candles is a sacred action. It expresses more than words can express. You may want to begin or end your day by the sacred ritual of lighting a candle. Or you may want to light a birthday candle for a friend. People say there is only one guideline: slow down and do it with full attention.
If you feel you would like to light a candle now in this very moment, you can. There is a lovely online light-a-candle site that guides you on the process. The first candles were lit in May 2001. Since then 12,642,389 candles have been lit from 243 countries.