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Introducing the Thermal Calendars tool
Mon, Mar 09, 2026
We are excited to introduce a new resource – the Thermal Calendars tool!
Tracking warmth accumulation in the northeastern U.S.
Temperature is an important factor governing when seasonal events happen in many plant and animal species. For many species, events like leaf-out, flowering, and egg hatch are triggered when a specific amount of heat has accumulated since the start of the year. We typically measure accumulated heat in growing degree days (GDDs).
Nature’s Notebook observations reveal clear changes in New Jersey
Mon, Mar 09, 2026
Global temperatures are increasing and the impacts are numerous and wide ranging. Temperatures have been rising at a particularly fast rate in the northeastern U.S., including many densely populated areas like New Jersey. To document environmental changes and better understand the impacts of climate change in this region since the mid-1960s, researchers gathered data on sea and air temperatures, lake ice, and snowfall. They complimented the weather data with observations of spring leaf-out and flowering in local lilac plants. The researchers found clear evidence of climate change, with notable increases in both daytime and nighttime temperatures and earlier spring plant activity. These changes will have numerous economic, social, and ecological impacts. Among other effects, earlier spring onset has the potential to alter plant-pollinator interactions and the length of the pollen and growing seasons.
Phenology Week! March 16-20, 2026
Tue, Feb 03, 2026
March 16-20, 2026 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! We'll have webinars, awards, daily challenges, observer stories, and more.