The best advice which I can give for tourists looking to partake in cannabis culture is to take care. It’s best to prevent yourself from marijuana use in public areas. It is now allowed to use on public grounds or federal property. The fine is $100 civil penalty for public consumption. Police are always looking out to write people up for DUIs.
Washington D.C. has legalized recreational marijuana, and these laws apply both to locals and travelers. Just ensure you know the laws as they differ greatly compared to other recreational legal states. Also ensure you step no where near federal property with marijuana as this could cause legal troubles. 2 ounces of weed or less is the legal amount to carry and you can also grow a small amount in Washington D.C.
Yes the laws for local are somewhat different than laws for visitors. Medical marijuana is legal Washington D.C. and recreational marijuana for adults was legalized in November 2014. You cannot get your medical marijuana card if you are not a Washington D.C. resident. But you can buy recreational marijuana if you are adult (21 years or older). Adults 21 and older may possess up to two ounces or less of marijuana. Please do not possess above the limit and transportation to others states is not allowed.