Calculate the number of frost days

This function calculates the number of frost days from a numeric vector of daily minimum temperatures using tidyverse principles.

Usage

number_frost_day(
  .data,
  threshold = get_weather_option("extreme.frost_threshold"),
  require_full_year = get_weather_option("require_full_year")
)

Arguments

.data

A data frame or tibble containing daily minimum temperatures in a column named "mint".

threshold

The stress temperature threshold for frost (default: 0)

require_full_year

Logical. If TRUE, requires exactly 365 or 366 days (default: TRUE)

Value

An data.frame or tibble representing the number of frost days, or 0 if no frost occurs

Examples

file <- system.file("extdata/ppd_72150.met", package = "tidyweather")
records <- read_weather(file)
records |>
    dplyr::group_by(year) |> 
    number_frost_day(require_full_year = FALSE)
#> # A tibble: 3 × 2
#> # Groups:   year [3]
#>    year number_frost_days
#>   <dbl>             <int>
#> 1  2023                 0
#> 2  2024                29
#> 3  2025                 9