Here are the definitions from the Working Assets web site: Night/Weekend: From 11:00 p.m. up to, but not including, 8:00 a.m. local time, Sunday through Friday, any time on Saturday, any time on Sunday except for the period beginning at 5:00 p.m. up to, but not including, 11:00 p.m. Holidays: All Carrier-specified holidays: New Year’s Day,† Martin Luther King Day,* Presidents’ Day,* Memorial Day,† Independence Day, Labor Day, Columbus Day, Veterans Day,† Thanksgiving Day, and Christmas Day.† * Applies to Federally observed day only. † When this holiday falls on a Sunday, the Holiday calling rate applies to calls placed on the following Monday. When this holiday falls on a Saturday, the Holiday calling rate applies to calls placed on the preceding Friday.