You mean next year, I guess? Usually the last weekend in January, IIRC, but it has been a bit unpredictable just lately!
Check on this link a bit nearer the time.
http://www.costadoradaonline.net/Eventos_Salou_Festiv_Invierno.html
if im wrong please forgive me but you are looking at the 2009 programe, it is to early for the 2010 programe, but if im correct on saying the first saturday in febuary is normally the cos blanc parade