According to the IRS website, WMR updates:
Sunday 12:00 am (Midnight) to 7:00 pm
Monday 12:00 am (Midnight) to 6:00 am
Tuesday 3:30 am to 6:00 am
Wednesday 3:30 am to 6:00 am
Thursday 3:30 am to 6:00 am
Friday 3:30 am to 6:00 am
Saturday 3:30 am to 6:00 am and 9:00 pm to Midnight

Based on experience and over the past 5 years I have monitored WMR and many discussion communities. For the past five years, we have only seen major updates with Direct Deposit Date to the WMR portal for Daily Accounts on Wednesday Mornings updating to Friday Direct Deposit Dates. Weekly accounts update on Saturday mornings with Wednesday Direct Deposit Dates.

Take a look at the schedule we use to determine the next Where’s My Refund? Updates here!