My rule of thumb is 90 days. I was taught that the chemicals need to dry properly/thoroughly so it will accept coatings. I think arsenic is used, know a guy who always handles pt lumber with gloves.
There's pressure-treated and then there's pressure-treated. Garbage from HD or Lowe's may have been sitting, unstrapped (which dries more quickly) for who knows how long. Higher-quality lumber bought in bulk & delivered from a commercial yard needs more time. Strapped & wrapped is what the yard guys call it here, protects from premature drying & buckling/twisting/bending of the planks.
Also depends on region, a deck in full sun in Arizona will dry more quickly than shaded decking in SC.
Whatever you do, don't use a surface cleaner on it, I think I read that somewhere...