Lethbridge ( /ˈlɛθbrɪdʒ/) (Ktunaxa: ʔa·kwum ) is a city in the province of Alberta, Canada, and the largest city in southern Alberta. It is Alberta's fourth-largest city by population after Calgary, Edmonton and Red Deer, and the third-largest by area after Calgary and Edmonton. The nearby Canadian Rockies contribute to the city's cool summers, mild winters, and windy climate. Lethbridge lies southeast of Calgary on the Oldman River.