Which mountain is the best to ski in mid-May?

The best place to ski mid-May (in my opinion) is without a doubt Timberline Ski Area. It is a short 1.5 hours from Portland. They do have a rental shop in case you don’t feel like traveling with your gear. Depending on what your free time looks like you can ski in the morning, hike in the afternoon, and be back in Portland for dinner.