if(months.grid == T) mtext(side = 1, xlab.text, line=2)
if(months.grid == T) axis(1, at=at, labels=F, line=4,
cex.axis=months.font, lab=NULL )  
if(months.grid == T) axis(1, at=at2, labels=months, line=4,
cex.axis=months.font, lab=NULL, tick=F,  mgp=c(3,0,0))