Home Page | USA National Phenology Network

USA National Phenology Network is a national-scale monitoring and research initiative focused on collecting, organizing and delivering phenological data, information, and forecasts to support natural resource management and decision-making, to advance the scientific field of phenology, and to promote understanding of phenology by a wide range of audiences.

Why phenology?

Phenology is nature’s calendar—when cherry trees bloom, when a robin builds its nest and when leaves turn color in the fall. Learn why phenology is vital to many aspects of ecology and society. Phenology is also a leading indicator of climate change.

Track the Status of Spring

See forecasts of pests and invasive species

Track changes in plants and animals

What's Happening

Phenology Week! March 17-21, 2025

March 17-21, 2025 is Phenology Week - a virtual celebration of the seasonal cycles of plants and animals. The purpose of Phenology Week is to celebrate YOU, our Nature's Notebook observers, Local Phenology Programs, and partners! Read more

The Phenophase Primer is here!

The Phenophase Primer for Flowering Plants: Understanding Plant Phenophases for Nature's Notebook, is finally here! Read more

An excerpt from Phenology (a book!) - available Mar 4

USA-NPN Director Theresa Crimmins' first book, Phenology, will be published as a part of the MIT Press Essential Knowledge series just in time for spring, on March 4! Read more

Download Nature's Notebook

Track seasonal changes in plants and animals throughout the year with Nature's Notebook.

To get started, download our Nature's Notebook app for Android or iPhone, or set up your account online.

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