I just got tints done this past Sunday. I got 15% on back 3 and 35% on front 2. Its been 3-4 days and it doesn't seem as dark as it should be for being 15%. I know the weather is wet and cold, how long should it take to be fully darkend and ready to go?

 

Wrong section..

 

It doesn't get darker, it does the opposite. Over time the tint actually fades.

 

He's right, it should be darker for a day or two until the tint dries. I think both sound too light, 5% in the back at least

 

He's right. Especially the cheaper tints. Be carefull in NJ, most places that are cheap use cheap film especially in Newark. I've had a few cars done (in Newark) and after a few months, when winding the window down, you can actually see a difference in shade compaired to the piece in the weather stripping when rolled up.
Also using some window cleaners will also speed up the fading process or discolor the tint. The only glass cleaner I use on my tinted cars is Invisible Glass cleaner made by Stoner. Hope that helps.