I always catch the giant whites (When I say giant I mean 2.5 lbs or better.) a good month before the "main " spawn takes place. Not to say I do not catch a giant during the main spawn, because I do. I just do not catch 3 or 4 in a day. More like 1 every other day. I have only caught the 3 pounders early nothing after late March. Just my experience.