A-Basin  and or Keystone should be open by the end of the month

https://www.vaildaily.com/news/get-excited-more-colorado-ski-resorts-start-making-snow-as-storms-and-favorable-weather-loom/

Per usual, getting open by Thanksgiving weekend is the goal for destination resorts in Colorado.

Colorado ski resort opening days for the 2025-26 season - Summit Daily, posted early September 2025, recently updated

OpenSnow has the Snowmaking forecast graphs available for free for a little while longer.  Here's what it looks like for ABasin 10/20 to 11/3.  Wonder if ABasin will open by Halloween?  Should be plenty of opportunity for snowmaking the last week of October, assuming they don't run out of water.