Using boxplot in a daily time series

Hi all,

I'm trying to plot my daily time series, with 3650 observations( 10 years),
with boxplot but I want 12 boxes, one for each month, can anyone help me
doing that.

Best regards

Sure,

there are several approaches to this, but in general thinking about your data 
in terms of 'grouping' factors can be helpful

example:

# 1 year's worth of dates:
d <- strptime(1:365, format="%j")

# some simulated data
x <- rlnorm(365)

# combine them into a DF 
dx <- data.frame(date=d, value=x)

# plot the data, note that x-axis is in dates:
plot(dx)

# now generate a grouping factor. how about months:
dx$month <- format(dx$date, format="%B")

# box and whisker plot for data *grouped* by month
boxplot(value ~ month, data=dx, las=3)


cheers,

Dylan