Meteorologically, winter ends on the last day of February. Astronomically, it ends around March 20th. However, practically speaking, many Americans consider winter "over" once the clocks spring forward in March, or after the spring equinox.
This is the definition most people recognize from grade school science. It is based on the Earth's tilt and its orbit around the sun. when is winter in united states
While the solstice is the shortest day, it is rarely the coldest. Due to "thermal lag" (the time it takes the ground and oceans to cool down), the coldest temperatures in the U.S. usually occur in mid-to-late January or early February. Meteorologically, winter ends on the last day of February