Our creatives work across different time zones. Some work more on weekends and holidays while others work more on weekdays
There is never a wrong time to start a contest, it ultimately depends on your availability. It's important that you are able to provide feedback while your contest is running.
Therefore, if you believe you will be able to review your submissions and provide feedback during weekends/holidays, then you can certainly launch it then. If during the week works better for you, please don't hesitate to do so.
As soon as you complete the final payment step, your contest will be immediately live, and you will start receiving suggestions within few minutes.