Saint Paul history and the city's growth as a landing port are tied to water. The city's defining physical characteristic, the Mississippi and connecting Minnesota Rivers were carved into the region during the last ice age. Fed by receding glaciers and Lake Agassiz ten thousand years ago, torrents of water from a glacial river undercut the river valleys.[34] The city is situated in east-central Minnesota.The Mississippi River forms a municipal boundary on part of the city's west, southwest and southeast sides. Minneapolis, the state's largest city lies to the west; Falcon Heights, Lauderdale, Roseville, and Maplewood are north; Maplewood is also to the east; the cities of West Saint Paul and South Saint Paul are to the south; and Lilydale, Mendota and Mendota Heights lie across the river from the city to the south. The city's largest lakes are Pig's Eye Lake, in the river, Lake Phalen, and Lake Como. According to the United States Census Bureau, the city has a total area of 56.2 square miles (145.5 km²). 52.8 square miles (136.7 km²) of it is land and 3.4 square miles (8.8 km²) of it (6.07%) is water

Saint Paul has a continental climate typical of the Upper Midwestern United States. Winters are frigid and snowy, while summer is comfortable and warm. At times however, it can be hot and humid. As a consequence of St. Paul's continental climate it experiences one of the greatest ranges of temperatures on earth. On the Köppen climate classification, Saint Paul falls in the warm summer humid continental climate zone (Dfa). The city experiences a full range of precipitation and related weather events, including snow, sleet, ice, rain, thunderstorms, tornadoes and fog.Due to its northerly location in the United States and lack of large bodies of water to moderate the air, Saint Paul is sometimes subjected to cold Arctic air masses, especially during late December, January and February. The average annual temperature of 45.4 °F (7 °C) gives the Minneapolis–Saint Paul metropolitan area the coldest annual mean temperature of any major metropolitan area in the continental U.S.