Yes, you can define a flow based on day and time.

Depending upon date

You can use a branch block and select the property "Current day" for creating the conditional check.
For conditional check, you can set up a date range, from a particular date(DD-MM-YYYY) to another date ((DD-MM-YYYY).

Depending upon time

You can use a branch block and set up the condition check using the property "Current hour" for a range of hours in a day. (The Current Hour property  works on GMT timezone and it should be kept in mind before defining the conditions).