The National Phenology Network provides maps that trace the movement of the spring “green wave” north as the year progresses. Citizen scientists track events like the first green leaf, the first bloom on a plum tree, and other weather-related biological signs to see how they vary from one year to the next. This year’s map shows that spring started off slow in Florida but was ahead of average in the southern states. Since then, more northern regions have been delayed by the recent cold spell. By comparison, spring 2020 started much earlier across the entire eastern US. You can look at more phenology maps at https://usanpn.org/.
