Rainfall Canberra last decade

rain_in_Canberra.R

library(tidyverse)
library(hrbrthemes)
library(ggrepel)
library(weatherBOM)

# Return day of the season
sday <- function(date, season = "summer") {
    switch(
        season,
        summer = if_else(month(date) %in% c(12, 1, 2), yday(date %m+% months(1)), NA),
        autumn = if_else(month(date) %in% 3:5, yday(date %m-% months(2)), NA),
        winter = if_else(month(date) %in% 6:8, yday(date %m-% months(5)), NA),
        spring = if_else(month(date) %in% 9:11, yday(date %m-% months(8)), NA))
}

# Colours
# Source: https://tsitsul.in/blog/coloropt/
col_normal12 <- c(
    "#EBAC23", "#B80058", "#008CF9", 
    "#006E00", "#00BBAD", "#D163E6", 
    "#B24502", "#FF9287", "#5954D6", 
    "#00C6F8", "#878500", "#00A76C", 
    "#BDBDBD")

# Get rainfall data using `https://github.com/mevers/weatherBOM`
data_plot <- weatherBOM::bom_historical_rain_data(070351) %>%
    mutate(
        day_in_summer = sday(date),
        FY = 1L + year(floor_date(date, unit = "month") - months(6))) %>%
    arrange(FY, day_in_summer) %>%
    filter(FY >= 2015 & FY < 2025, !is.na(day_in_summer)) %>%
    group_by(FY) %>%
    mutate(cum_mm_rain = cumsum(replace_na(mm_rain, 0))) %>%
    ungroup() %>%
    mutate(FY = sprintf("%s/%s", FY - 2000 - 1, FY - 2000))

# Plot
data_plot %>%
    ggplot(aes(day_in_summer, cum_mm_rain, colour = FY)) + 
    geom_step(linewidth = 1.01) + 
    geom_point(
        data = data_plot %>% 
            filter(FY == "23/24") %>%
            filter(day_in_summer == max(day_in_summer)),
        size = 3,
        show.legend = FALSE) +
    geom_text_repel(
        data = data_plot %>% 
            group_by(FY) %>%
            filter(day_in_summer == max(day_in_summer)) %>%
            ungroup(),
        aes(label = FY),
        nudge_x = +4,
        nudge_y = +3,
        segment.size = 0,
        direction = "y") +
    theme_ipsum_rc(plot_margin = margin(10, 10, 10, 10)) + 
    scale_colour_manual(values = rev(col_normal12[1:10])) +
    scale_y_continuous(name = "Cummulative rain fall (in mm)") +
    scale_x_continuous(
        name = "Day in summer",
        breaks = c(1, 15, 31 + 1, 31 + 15, 31 + 30 + 1, 31 + 30 + 15),
        labels = c("Dec", "15", "Jan", "15", "Feb", "15"),
        expand = expansion(mult = c(0, 0.1))) + 
    annotate("text", x = 25, y = -17, label = "\U1F384") +
    coord_cartesian(ylim = c(0, 250), clip = "off") +
    labs(
        title = "2023/2024 is the wettest Canberra summer in (more than) a decade",
        subtitle = "Cumulative rainfall during the three summer months, starting 1 Dec",
        caption = paste(
            "[Rainfall data source: Bureau of Meteorology, Canberra Airport station]",
            "[Visualisation: https://gist.github.com/mevers/66d778b59b451500fb6b62d730c51121]",
            sep = "\n")) +
    theme(
        plot.title.position = "plot",
        plot.tag.position = c(25, -10),
        legend.position = "none",
        panel.grid.minor.x = element_blank(),
        panel.background = element_rect(fill = 'white', colour = 'white'),
        plot.background = element_rect(fill = 'white', colour = 'white'))
ggsave("why_does_it_always_rain_on_me.png", height = 7, width = 7)