What is the most elegant way to split data and produce seasonal boxplots?

Question

I want to produce seasonal boxplots for a lot of different time series. I hope that the code below clearly illustrates what I want to do.

My question is now, how to

Answer 1

Using 'ggplot2' (and @James' month names, thanks!):

DF$month <- factor(strftime(DF$Time,"%b"),levels=month.abb)
ggplot(DF, aes(x=,month, y=Data)) +
    geom_boxplot()

(BTW: note that in 'ggplot2' "The upper and lower "hinges" correspond to the first and third quartiles (the 25th and 7th percentiles). This differs slightly from the method used by the boxplot function, and may be apparent with small samples." - see documentation)