The United States experienced its warmest March on record, with temperatures averaging 7°F above normal, leading to the early emergence of leaves and flowers across much of the country. According to the USA National Phenology Network, leaves have appeared two to four weeks earlier than usual in many Central and Western states, affecting approximately 190 million people. Areas near the Rocky Mountains and the central Plains, from Kansas to South Dakota, saw leaves emerge 30 to 50 days ahead of schedule. In contrast, the Carolinas and parts of Virginia experienced a delayed leaf-out due to a colder winter. The early onset of spring is attributed to the accumulation of warmth, measured by growing degree days, which has been significantly higher this year.