How to assign unique point colors in faceted ggplot

I am making a facet plot and trying to select the color I want for each plot (olivegreen and olivegreen3 in this case). I need to plot temp versus lat faceted by year


library(tidyverse)
d.f. <- data.frame( year = c(rep(2013, 10),rep(2015,10)), temperature = rep(c(1:10),2), lat = rep(c(70:79),2))


  ggplot(data = d.f., aes(x=temperature, y = lat)) +
  geom_point(show.legend = FALSE, size = 3) + 
  facet_wrap(~year)  +
  xlab("Surface Temperature") +
  ylab("Latitude")

I am sure it is a simple fix, and perhaps I'm tired this Friday but I cannot figure out how to make the points in each facet different colors of my choosing. When I do color = year in the aes() argument that makes them unique colors, but automatically picked.

Solution

By default, year will be a numeric vector, so you'll need to coerce year to a factor. Then you can configure the color scale manually:

ggplot(data = d.f., aes(x=temperature, y = lat, color = factor(year))) +
  geom_point(show.legend = FALSE, size = 3) + 
  scale_color_manual(values = c("darkolivegreen", "darkolivegreen3"))+
  facet_wrap(~year)  +
  xlab("Surface Temperature") +
  ylab("Latitude")