Convective precipitation and lightning are two physically related phenomena of thunderstorms. Several studies have calculated rain yields over various temporal and spatial scales for different climatic regimes around the world, however, such studies have not been carried out across Canada.

In this study, fifty three weather stations reflecting different precipitation regimes across Canada were selected. The study period comprised the months of April to October from 1999 to 2003. The components of rain yield, namely, C-G lightning flashes and rainfall were obtained from the Canadian Lightning Detection Network, and the daily rainfall measurements reported at each of the stations on confirmed thunderstorm days from the MSC surface weather archive. All C-G lighting strikes detected within a 20-km radius of each station were used in the calculation of the rain yield. We assumed the same rain depth over the entire 20-km radius, and calculated the rain yield by taking the ratio of the volume of precipitation to the total number of C-G flashes. Thunderstorm days were stratified as either wet or dry according to the precipitation amount recorded at the station. Thunderstorm days were considered wet if the rainfall amount was greater than 3 mm, and dry if the rainfall amount was less than 3 mm.

Rainfall-lightning characteristics for eastern and western Canadian locations as well northern and southern locations were compared. The geographic differences in rainfall-lightning relationships reflect the complexity of thunderstorm characteristics and structure across the country. Rainfall is better related to lightning flashes for stations in the North than elsewhere.