Sometimes it snows in July! Forest fires or falling boulders may also cause road closures. You can check road conditions here.
A weather station will be set up at the Research Station during the 2017 season. In the meantime, you can view the weather data from Moran, the town closest to the station (about 11 miles away), or Yellowstone National Park.
See current conditions at Pilgrim Creek on the phenocam.