"This is most definitely the first time Missoula's median sales price has eclipsed $300,000," he said. "What we saw in April and May was a surge of houses go under contract, and extremely tight supply."

Then, when those sales were finally recorded in June, it led to a spike in the median sales price.

Wahlberg said he expects the market to cool down this fall and winter as it did last year, but he still wouldn't be surprised if the median sales price climbs another $10,000 or $15,000 by year's end.

"Our median in August of last year was like $297,000 and through the fall peeled back as the crazy summer, the insane part of the market, cooled down and we hit the regular fall market," he said. "But what this probably means now is when a neighbor down the street sees a house sold for $305,000, they're not going to list theirs at $295,000 now. They're going to list at $305,000 and the median will keep climbing."

John Brauer, a past president of the Missoula Organization of Realtors, said out-of-state buyers with money are definitely helping to push up prices.