as.POSIXlt('2014-11-04')$wday POSIXlt The POSIXlt data type is a vector, and the entries in the vector have the following meanings: sec 0–61: seconds min 0–59: minutes hour 0–23: hours mday 1–31: day of the month mon 0–11: months after the first of the year. year Years since 1900. wday 0–6 day of the week, starting on Sunday. yday 0–365: day of the year. isdst Daylight savings time flag. Positive if in force, zero if not, negative if unknown.