Rust updates always come the first Thursday of the month.
This will wipe both the map and user data.
The time of update varies widely, but is usually between:
7:00 - 9:00 PM GMT",

Actual update time depends how much work Facepunch needs to resolve any last-minute bugs.


Wipe Schedule
Valhalla has a 14 day wipe schedule.
That means a full wipe on the first Thursday of the month, and a map wipe on the 14 in order to reduce server lag.