Date/DateTime character -> Seasonal character

This function transforms a character vector of Dates or DateTimes into a character vector of seasons (summer, winter, autumn, spring), depending on the value of type:

When type=default -) winter = DJF: December, January, February
-) spring = MAM: March, April, May
-) summer = JJA: June, July, August
-) autumn = SON: September, October, November

When type=FrenchPolynesia -) winter = DJFM: December, January, February, March
-) spring = AM : April, May
-) summer = JJAS: June, July, August, September
-) autumn = ON : October, November

When type=SONDJFM -) SONDJFM: September, October, November, December, January, February, March, with January, February and March belonging to the next calendar year. Leading January, February and March values before the first September season are returned as NA. Other months are returned as NA.

Usage

time2season(x, out.fmt = "months", type="default")

Arguments

x: vector with the dates that have to be transformed. class(x) must be Date
out.fmt: character, indicating the format of the output seasons. Possible values are:
-) seasons => c("winter", "spring", "summer", autumn") or "SONDJFM" when type="SONDJFM"
-) months => c("DJF", "MAM", "JJA", SON") or c("DJFM", "AM", "JJAS", ON") or "SONDJFM"
type: character, indicating which weather seasons will be used for computing the output. Possible values are:
-) default => "winter"= Dec, Jan, Feb; "spring"= Mar, Apr, May; "summer"=Jun, Jul, Aug; "autumn"= Sep, Oct, Nov
-) FrenchPolynesia => "winter"= Dec, Jan, Feb, Mar; "spring"= Apr, May; "summer"=Jun, Jul, Aug, Sep; "autumn"= Oct, Nov
-) SONDJFM => "SONDJFM"= Sep, Oct, Nov, Dec, Jan, Feb, Mar; other months are returned as NA

Value

character vector with the weather season to which each date in x belongs

Author

Mauricio Zambrano-Bigiarini, mzb.devel@gmail

Note

Weather seasons corresponding to French Polynesia were defined following a comment from Lydie Sichoix

Examples

## Sequence of daily dates between "1961-01-01" and "1961-12-31"
t <- dip("1961-01-01", "1961-12-31")
time2season(t)
#>   [1] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#>  [13] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#>  [25] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#>  [37] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#>  [49] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "MAM"
#>  [61] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#>  [73] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#>  [85] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#>  [97] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#> [109] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#> [121] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#> [133] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM"
#> [145] "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "MAM" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [157] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [169] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [181] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [193] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [205] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [217] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [229] "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA" "JJA"
#> [241] "JJA" "JJA" "JJA" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [253] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [265] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [277] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [289] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [301] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [313] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON"
#> [325] "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "SON" "DJF" "DJF"
#> [337] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#> [349] "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF" "DJF"
#> [361] "DJF" "DJF" "DJF" "DJF" "DJF"

## Sequence of monthly dates between "1961-01-01" and "1961-12-31"
t <- mip("1961-01-01", "1961-12-31")
time2season(t)
#>  [1] "DJF" "DJF" "MAM" "MAM" "MAM" "JJA" "JJA" "JJA" "SON" "SON" "SON" "DJF"
time2season(t, out.fmt="seasons")
#>  [1] "winter" "winter" "spring" "spring" "spring" "summer" "summer" "summer"
#>  [9] "autumn" "autumn" "autumn" "winter"

## September to March selector
time2season(t, type="SONDJFM")
#>  [1] NA        NA        NA        NA        NA        NA        NA       
#>  [8] NA        "SONDJFM" "SONDJFM" "SONDJFM" "SONDJFM"