You can use your Connecticut medical marijuana card in some states that recognize medical marijuana reciprocity, but not everywhere. Each state sets its own rules, and while a few allow out‑of‑state patients to purchase directly, others only grant limited legal protections or require you to apply for a temporary visitor card.
There is no national system for medical marijuana cards. Instead, each state decides whether to honor cards from other states. This creates a patchwork of rules that patients must navigate when traveling. You are always best-off checking with a shop in the area you will be visiting ahead of time to check.