Temperatura de Porto Alegre

ggplot() +
  geom_errorbar(data = d, aes(dia, ymin = tmin, ymax = tmax), colour = "salmon", alpha = .35, size = 1) +
  geom_point(data = dias_quentes, aes(data, temp_max), fill = "firebrick2", colour = "gray20", shape = 21, size = 3) +
  geom_point(data = dias_frios, aes(data, temp_min), fill = "dodgerblue3", colour = "gray20", shape = 21, size = 3) +
  geom_line(data = d, aes(dia, tmedia, group = 1), colour = "black", size = 1) +
  labs(x = "", y = "", title = "Temperatura em Porto Alegre (07/2017-07/2018)",
       caption = "Fonte: CPTEC",
       subtitle = "Temperatura registrada a cada hora do dia. As barras indicam a maior e a menor temperatura do dia.\nA linha escura representa a temperatura média de cada dia.\nOs dias mais frios/quentes estão indicados pelos círculos azuis/vermelhos.") +
  scale_x_date(date_breaks = "1 month", date_labels = "%b", expand = c(.01,0)) +
  scale_y_continuous(breaks = seq(0, 40, 5), labels = paste(seq(0, 40, 5), "º", sep = "")) +
  theme_classic() +
  theme(
    panel.grid.major.x = element_line(colour = "wheat4", linetype = 3, size = .5),
    text = element_text(family = "Georgia"),
    plot.title = element_text(size = 18),
    plot.subtitle = element_text(size = 8)
  )