You'll want to watch for the the trichomes to darken-up, not the 'hairs'.
If it's been 4 weeks, you probably have 2-4 weeks to go.
Rusty Trichome Reviewed by Rusty Trichome on . turning amber when in flowering when do they start turning amber color cause im a little over 4 weeks and its skunk#1 and a couple of the hairs have a little bit of amber color in them and the rest are still clear? Rating: 5