Get past air quality forecasts

get_airnow_forecast_history() retrieves forecasts that were valid on dates in the given range for one reporting area. Every forecast lead time is returned unless range narrows it: range = 1 keeps only the forecast issued the day before each valid date.

Usage

get_airnow_forecast_history(
  area,
  start_date,
  end_date,
  range = NULL,
  parameter = NULL,
  clean_names = TRUE,
  api_key = get_airnow_key()
)

Arguments

area

Reporting area code such as "ca064" (required). See airnow_areas or get_airnow_reporting_area().

start_date, end_date

First and last valid date to include, as Date objects or "YYYY-MM-DD" strings. AirNow serves these forecasts only through today, so a future date returns no rows and warns. Use get_airnow_forecasts() for upcoming forecasts.

range

Optional forecast lead time in days to keep (a positive whole number). NULL (default) keeps every lead time.

parameter

Optional pollutant to keep: one of "ozone", "pm2.5", "pm10", "co", "no2", "so2".

clean_names

Whether column names should be converted to snake_case (default: TRUE). With FALSE, the API's lowerCamelCase names are kept.

api_key

AirNow API key

Value

A tibble with the same columns as get_airnow_forecasts().

Requests made

One request per call. Every request counts against AirNow's limit of 500 requests per hour per key.

See also

get_airnow_reporting_area() to find the area code for a ZIP code or coordinates; get_airnow_forecasts() for current forecasts.

Examples

if (FALSE) { # \dontrun{
get_airnow_forecast_history("md008", "2026-01-13", "2026-01-14")
get_airnow_forecast_history("md008", "2026-01-13", "2026-01-13",
  range = 1, parameter = "pm2.5"
)

# Starting from a ZIP code
area <- get_airnow_reporting_area(zip = "90210")$reporting_area_code
get_airnow_forecast_history(area, "2026-09-01", "2026-09-03", range = 1)
} # }