Update: we have moved the monthly Windows update to the second Wednesday of each month. This allows us to get the updates and security patches installed closer to when they are released. We run the automated Windows Server Update Services on the second Wednesday of every month. This affects all the servers that run Windows O/S, which includes almost all of the customer-facing servers (web, SQL, etc.). This shouldn't affect your sites, since the web servers aren't all updated at the same time. But it will occasionally affect the shared SQL servers. The monthly Windows update happens on the second Wednesday of every month, from approximately 6:00 p.m. to 3:00 a.m. Pacific time. During that time the automated Windows Server Update Services will run. Depending on what is done to the servers a reboot may be necessary, which will extend the update by 5 or 10 minutes. We can't say how long the maintenance will take each month - some months there may be no interruption at all. The potential disruption depends on what Microsoft sends out to the service. Note also that Wednesday is our weekly maintenance window as well. So if any maintenance needs to be done outside of the automated Windows Server Update Services, you can anticipate it being done on a Wednesday evening. Everleap serves customers worldwide, so unfortunately there is no ideal time to perform updates. We base our weekly maintenance window on the point that traffic on our network is at its lowest, and that is Wednesdays from approximately 6:00 p.m. to 3:00 a.m. Pacific time.