The Breakdown:

As of July 15th, it has been legal for medical marijuana dispensaries to open in Hawaii.
Hawaii dispensaries are not ready to open their doors yet for one big reason - they need testing labs.
The Details:
Hawaii's Department of Health requires marijuana testing facilities to check cannabis products for quality, pesticides, harmful microbes, and more.
There has yet to be applicants from any laboratories to become certified by the Hawaii Department of Health, although one lab, Spectra Analytical Lab, is working on an application.
Until products can be tested by an approved lab, the dispensaries are unable to open.
There are eight approved dispensaries waiting for an approved lab to fill the gap.
References & Further Reading:
"Hawaii Cannabis Dispensaries Can Legally Open, but None are Ready" - (The Associated Press via Leafly)
Image Credit - (Wikimedia Commons)