As the calendar declares the arrival of spring, nature offers its own nuanced perspective. Across the United States, the emergence of new leaves and spring blossoms, coupled with the northward migration of birds, paints a complex picture of a season unfolding at varying paces.
The USA National Phenology Network reports a steady northward progression of spring leaf-out across the country. However, the eastern region presents a mosaic, with spring arriving earlier than the long-term average in some areas while lagging in others. The Network’s maps track the subtle cues of biological activity, revealing the nuances of spring’s progression.
Southern Delay: Many locations in the southern half of the U.S. experienced a slightly later-than-usual start to spring.
Northern Surge: The leading edge of spring conditions is now moving northward into Illinois, Indiana, and Pennsylvania, appearing ahead of schedule.
“Only little chunks of the country have had an early season,” said Theresa Crimmins, an associate professor at the University of Arizona and the network’s director. However, she expects that to change as spring indicators in southern Nebraska, the southern half of Iowa and creeping into northern Illinois, Indiana, Ohio and southern Pennsylvania, are starting next week and it will be ahead of schedule by a week to two weeks.
Leaf Emergence: Red maples and silver maples are budding, sumac species are developing flower buds, and lilacs are awakening.
