Whether you're a Centennial State resident or you're planning to take a trip there, you may be wondering how old you have to be to smoke weed in Colorado. Since January 1, 2014, it has been legal for anyone at least 21 years of age (resident and visitor alike) to buy retail marijuana flowers, concentrates, and other products for his or her own recreational or medicinal use.
However, it is illegal for anyone under of 21 to possess or consume cannabis, so even if you have the state's “red card” and you're no longer a minor (at least 18 years old) you won't be able to buy weed to smoke for yourself. You have to rely on your legally recognized primary caregiver to obtain your cannabis medicine and administer it to you.
Colorado's rules and regulations regarding cannabis state that residents and tourists alike can buy and possess 1 ounce of the herb while within the state's borders. Remember, it's still illegal to transport cannabis across state lines by plane, train, or automobile (or by mail) even if you're old enough to smoke weed in Colorado.
You have to be 21 years old to smoke weed in Colorado, but just because you're of age doesn't mean you have the liberty to light up wherever you please. The state has strict rules against smoking (or consuming in any way) marijuana in openly in public, as it's meant to be used in the privacy of one's home or establishments that specifically cater to the cannabis community, like weed-friendly hotels and members-only smoking clubs. At this time “coffee shops” and “pot bars” where smoking weed is acceptable aren't allowed in Colorado like they are in Amsterdam, though that may change. For example, the city of Denver allows passengers in the rear seats of private, for-hire transportation vehicles to smoke weed if the company allows for it, but the driver and any passengers in the front seat can't partake.
That's just the way it is folks; unless there's a change in the state's legislature on cannabis, you have to be 21 years old to smoke weed in Colorado.