Washington plans to keep the weed for locals
(Read more: In two states, corner cannabis store nearing reality)
While Colorado is preparing for an influx of pot-smoking tourists, Washington will try to head them off by limiting the supply to people who live in the state.
The state commissioned the nonprofit research institution RAND to provide data on how much pot Washington residents consume—and it turns out to be way more than expected.
(Read more: WeedMaps: Meet the Yelp of the marijuana business)