Peak Fares are charged during business rush hours, on any weekday train scheduled to arrive in NYC terminals between 6 and 10 AM or depart NYC terminals between 4 and 8 PM.
Off-Peak Fares are charged all other times on weekdays, all day on Saturdays and Sundays and holidays as listed below.
Holidays - Off-Peak Fares are valid and LIRR trains operate on a weekend schedule on the following holidays: New Year's Day, Martin Luther King, Jr. Day, President's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day.
Black Friday - Off-Peak Fares are valid all day even though LIRR trains operate on a weekday schedule on the day after Thanksgiving.
Senior/Disabled & Medicare tickets will be honored all day on the holidays listed above and on Columbus Day, Election Day and Veterans Day.

Metro-North Railroad Schedules