Interior work can happen year-round, but anything that opens the house to the weather, touches the foundation, or needs materials trucked over a pass has a season. In the Roaring Fork Valley that season runs roughly May through October, and every builder in the valley is trying to fit their work into it.
The practical answer is to plan in winter. Get your estimate, engineering, and permit applications done between January and March, order long-lead materials like windows, cabinets, and specialty flooring before spring, and lock a start date so you're at the front of the line when the ground thaws.
Sequence the project so the weather-exposed work happens first. Demolition, framing, roofing, and siding go in the dry months. Drywall, flooring, trim, and paint can run into fall and winter once the house is dried in, which is also when good crews have more availability.
And build a buffer. Inspections take longer in peak season, deliveries slip, and a week of early snow can pause exterior work. A written schedule with a start date, a finish date, and honest contingency is worth more than an optimistic one. Ask for it before you sign.