Renviron file by adding the line WUNDERGROUNDID = 'your key here'. Alternatively you can save the key in your local. You only have to do this once per R session. Once you have your API key as indicated above you can set the key in R using: rwunderground::set_api_key('YOUR KEY').

Afterwards install rwunderground using devtools: devtools::install_github('ALShum/rwunderground'). If you don't have devtools install using install.packages('devtools'). To install the latest version please use devtools. This package is officially on CRAN install using install.packages('rwunderground'). Has functions that follow the online api. If you are grabbing weather for a large date range using history_range then by default limit = 10 will limit the calls to a maximum of 10 per minute. Please note that the free tier also limits requests to 10 per minute. The free-tier should be sufficient if you aren't calling the API more than a 500 times per day. In order to use this library please register for an API key. This is an R interface to weather underground's API.

Wunderground historical weather