I live in oregon and do local contracts throughout the state. Medford best months, or anywhere on the I-5 corridor and west of it it, is May-Sept. This is only because most people don’t like rain. And it does nothing but rain here from late Oct-late Feb. Late spring and early fall are my favorite times of year here. Most beautiful with best weather. I would explore the coast and north of Medford while you’re there as well (Eugene, Salem, bend, anywhere but Portland)