Here’s a link to the academic calendar released this week by the chancellor’s office. Note is has a start date for the spring 2021 semester of January 25. This is the note from the chancellor and the provost about how classes and other activities will be conducted in spring, also released this week.
This is the complete spring 2021 plan for Danforth Campus as laid out on the university’s COVID-19 website.
Update, November 25, 2020: This is the WashU Olin academic calendar.