Trevor Hughes

USA TODAY

Marijuana tourists continue flocking to Colorado, but Washington has seen a slight decrease in travel interest since it became only the second state to allow recreational pot sales, a new study finds.

The study by Massachusetts-based travel firm Hopper showed interest in Washington has dropped 2% since legal recreational sales began July 8. In contrast, interest in Colorado is up 20% since the state's recreational market launched Jan. 1, according to the study.

Hopper's data experts compared Colorado's trend to other ski destinations to make sure it wasn't this winter's snowfall that drove the interest. They also checked to make sure Washington's decrease wasn't part of an overall decline in interest about the Pacific Northwest. Hopper's study is based on data gathered from one billion travel queries made daily.

Colorado vs. Washington on marijuana tourism

The study says the scarce supply of pot in Washington, which has driven prices up $5-$10 a gram compared to Colorado, is likely a factor.

Airplane ticket prices may also be playing a role: Over the past month, average domestic round-trip prices to Denver have been around $179 while prices to Seattle have been around $245, Hopper's study found.

"We never saw that spike in traffic," said Hopper data analyst Virginia Nicholson, who began tracking travel interest several weeks before Washington began recreational sales. "I think a lot of that has to do with the hurdles that Washington state faced from the start."

Washington's legal marijuana market has opened far more slowly than Colorado's, and some stores have reported running out of product. Additionally, Washington's market launched without any marijuana edibles, which have played a significant role in Colorado's booming pot economy.

"The early data overwhelmingly demonstrates that Colorado's program is a success," Mike Elliot of the pot-industry organization Marijuana Industry Group said in a statement earlier this month. "The dire predictions of our opponents have failed to materialize. Colorado is seeing record tourism, record real estate, and increases in tax revenue and jobs."

A Colorado state report released earlier this month found that tourists are buying up to 90% of the recreational pot sold in some Colorado ski towns. That study also said Colorado residents will consume about 121.4 metric tons annually, while tourists will buy nearly 9 metric tons. Colorado has collected $34.8 million in marijuana taxes and fees this fiscal year.

Colorado's ski resorts have taken great pains to remind both residents and tourists alike that smoking marijuana in public is illegal, and that it's also illegal to use it on the U.S. Forest Service lands that underlay most of the state's ski areas.

Several Colorado-based companies have begun offering marijuana tours to visitors, offering to pick them up and chauffeur them to pot shops before delivering them to the ski slopes.