Do you have scheduled fixed day(s) of a month for downtime to patch each critical system?

For OS patches, weekly reboots, almost all are fully scripted.  For cloud IaaS systems not in use are off and will come up for 4 hours one day a week to ingest the patch, update itself and then shut down.

I chose other as we have a maintenance weekend scheduled for each month throughout the year that may entail various system updates, changes or patches but we also have unscheduled updates depending on the severity or criticality of the patch or update required.

I replied with "Others" as we have planned and fix days for system maintenance.  But for a patch, depending of the criticity of the system and the severity of the breach/issue the be fixed, it could be a overnight patch.

We patch systems as soon as possible. We build new updated images every week. All patches are applied without downtime even db updates

We used to have a fixed day of the month but with modern operating systems we find most patching can now  be done w/out downtime. As others have said, criticals/sev 1 get done ASAP, others can wait, and if downtime is required, scheduled in advance.