Determine season from Date using lubridate in R

Question

I have a very big dataset with a DateTime Column containing POSIXct-Values. I need to determine the season (Winter - Summer) based on the DateTime

Answer 1

Use the POSXlt instead of POSXct.

I made my own function depending on the definition of seasons that I am using. I created vectors named normal for a non-leap year and leap for leap year with each season name repeated the no. of times it appears starting from Jan 1. And created the following function.

SEASON <- function(datee){
  
  datee <- as.POSIXlt(datee)
  season <- vector()
  normal <- rep(c("Winter","Spring","Summer","Monsoon","Autumn","Winter"), c(46,44,91,77,76,31))
  leap <- rep(c("Winter","Spring","Summer","Monsoon","Autumn","Winter"), c(46,45,91,77,76,31))

  
  if(leap_year(year(datee)) == FALSE){
    season <- normal[datee$yday+1]
  } else {
    season <- leap[datee$yday+1]
  }
  return(season)
}

Let's put it to test for some dataset.

Dates <- seq(as.POSIXct("2000-01-01"), as.POSIXct("2010-01-01"), by= "day")
sapply(Dates, SEASON)

It works.