How to align the x-axis of two different time series plots in R, adapted from https://gist.github.com/boboppie/f115b2e1f0004a9d0623

AlignDateXAxes.R

library(ggplot2)
library(grid)
library(lubridate)

# Create some data to play with. Two time series with offset timestamp.
df1 <- data.frame(DateTime = ymd("2010-07-01") + c(0:8760) * hours(2), series1 = rnorm(8761))
df2 <- data.frame(DateTime = ymd("2011-07-01") + c(0:8760) * hours(2), series1 = rnorm(8761))

# Create the two plots.
plotme <- function(inputdf,titletext,whatcolor){
  ggplot(inputdf, aes(x = DateTime, y = series1)) +
    geom_point(size = 0.5, alpha = 0.75, color = whatcolor) +
    ylab(titletext) +
    theme_minimal()}

p1<-plotme(df1,"Red Dots","red")+
  theme(axis.title.x = element_blank())+
  ggtitle("Aligned DateTime X axes")
p2<-plotme(df2,"Blue Dots","blue")+
  xlab("Date")

#Get the limits of each plot
lim1<-ggplot_build(p1)$layout$panel_ranges[[1]]$x.range
lim2<-ggplot_build(p2)$layout$panel_ranges[[1]]$x.range

#find max/min
x_min<-as_datetime(min(c(lim1,lim2)))
x_max<-as_datetime(max(c(lim1,lim2)))

#rescale to be the new limits of both plots
p1 <- p1 + scale_x_datetime(limits=c(x_min, x_max))
p2 <- p2 + scale_x_datetime(limits=c(x_min, x_max))

#plot together
grid.newpage()
grid.draw(rbind(ggplotGrob(p1), ggplotGrob(p2), size = "last"))

AlignedDateXAxes.jpg