Weekly on Wednesdays, 7:00 PM. The Venue's Website does not mention it.
The venue's own 2026-2027 season page does not mention an open mic anywhere, and its programming as a large opera house is a poor fit for a weekly bar-style open mic (checked Aug 14, 2026) [s1]. A different Oshkosh venue, New Moon Cafe, does have a confirmed open mic, but on Tuesday, not Wednesday, which weakens rather than supports the idea that the wrong venue was simply named here [s2].
A listing on openmikes.org lists this night, but may not be current.
Weekly on Mondays. Only one source reports it.
The Monday day is consistent across three separate months pulled from the same open-mic listing site, but a single listing site is treated only as one possible source, never as confirmation, however internally consistent. No venue-level source exists.