Sony selected this time frame because it was “ideal” for not interrupting game time for users. This time was chosen because it would not highly conflict with game time due to school or work schedules.
Mathew Harper, a member of the PlayStation Digital Platforms Community Management team announced
via Playstation Blog:
I’m here today to let you know that we will be performing routine scheduled maintenance on the network on Monday, April 16th, starting at approximately 6:00 am PDT / 9:00 am EDT. This maintenance will last roughly 13 hours, concluding around 7:00pm PDT / 10:00 pm EDT. During much of this time, users won’t be able to access the PlayStation Store, PlayStation Home, Account Management or play online. PSN enabled websites will not be able to service users, including this one.
Downtime will affect users across the world and not just the United States.