Adjective
multiday (not comparable)
Extending over multiple days.
Each year, every city in the world that can should have a multiday festival. More people meeting each other, digging new types of music, new foods, new ideas. You want to stop having so many wars? This could be a step in the right direction. Henry Rollins
And there are world records of Beach Walking on non-compact sand in Multiday distances. Source: Internet