Plot monthly means and add long-term mean annual discharge percentages. Calculates statistics from all values, unless specified. Mean data calculated using calc_longterm_daily_stats() function. Returns a list of plots.

  dates = Date,
  values = Value,
  groups = STATION_NUMBER,
  roll_days = 1,
  roll_align = "right",
  water_year_start = 1,
  months = 1:12,
  plot_months = 1:12,
  complete_years = FALSE,
  ignore_missing = FALSE,
  include_title = FALSE,
  percent_MAD = c(10, 20, 100)



Data frame of daily data that contains columns of dates, flow values, and (optional) groups (e.g. station numbers). Leave blank or set to NULL if using station_number argument.


Name of column in data that contains dates formatted YYYY-MM-DD. Only required if dates column name is not 'Date' (default). Leave blank or set to NULL if using station_number argument.


Name of column in data that contains numeric flow values, in units of cubic metres per second. Only required if values column name is not 'Value' (default). Leave blank if using station_number argument.


Name of column in data that contains unique identifiers for different data sets, if applicable. Only required if groups column name is not 'STATION_NUMBER'. Function will automatically group by a column named 'STATION_NUMBER' if present. Remove the 'STATION_NUMBER' column beforehand to remove this grouping. Leave blank if using station_number argument.


Character string vector of seven digit Water Survey of Canada station numbers (e.g. "08NM116") of which to extract daily streamflow data from a HYDAT database. Requires tidyhydat package and a HYDAT database. Leave blank if using data argument.


Numeric value of the number of days to apply a rolling mean. Default 1.


Character string identifying the direction of the rolling mean from the specified date, either by the first ('left'), last ('right'), or middle ('center') day of the rolling n-day group of observations. Default 'right'.


Numeric value indicating the month (1 through 12) of the start of water year for analysis. Default 1.


Numeric value of the first year to consider for analysis. Leave blank or set well before start date (i.e. 1800) to use from the first year of the source data.


Numeric value of the last year to consider for analysis. Leave blank or set well after end date (i.e. 2100) to use up to the last year of the source data.


Numeric vector of years to exclude from analysis. Leave blank or set to NULL to include all years.


Numeric vector of months to include in analysis. For example, 3 for March, 6:8 for Jun-Aug or c(10:12,1) for first four months (Oct-Jan) when water_year_start = 10 (Oct). Default summarizes all months (1:12).


Numeric vector of months to include on the plot after calculating statistics. For example, 3 for March or 6:8 for Jun-Aug. Differs from 'months' argument where that argument filters for specific months, this one just chooses which months to plot. Default 1:12.


Logical values indicating whether to include only years with complete data in analysis. Default FALSE.


Logical value indicating whether dates with missing values should be included in the calculation. If TRUE then a statistic will be calculated regardless of missing dates. If FALSE then only those statistics from time periods with no missing dates will be returned. Default FALSE.


Logical value to indicate adding the group/station number to the plot, if provided. Default FALSE.


Numeric vector of percentages of long-term mean annual discharge to add to the plot (ex. 20 for 20 percent MAD or c(5,10,20) for multiple percentages). Set to NA for none. Default c(10,20,100).


A list of ggplot2 objects for with the following plots for each station provided:


a plot that contains annual means with the long-term mean as the x-axis intercept


# Run if HYDAT database has been downloaded (using tidyhydat::download_hydat())
if (file.exists(tidyhydat::hy_downloaded_db())) {

# Plot monthly means
plot_monthly_means(station_number = "08NM116",
                   complete_years = TRUE)

# Plot mean flows with custom LTMADs
plot_monthly_means(station_number = "08NM116",
                   complete_years = TRUE,
                   percent_MAD = c(5,10,20,100))
# Plot mean flows and plot just summer months
plot_monthly_means(station_number = "08NM116",
                   complete_years = TRUE, 
                   plot_months = 6:9)
#> $Monthly_Means
#> Warning: Removed 8 rows containing missing values (`position_stack()`).