USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Status of Spring

The USA-NPN is tracking the start of the spring season across the country using models called the Spring Leaf and Bloom Indices. 

How does this spring compare to "normal"?

Spring continues to arrive early in the west and late in the east, compared to a long-term average (1981-2010). Spring is four weeks early in southern Utah and eastern Washington and 5-6 weeks early in the Grand Canyon. Spring is a few days late in Birmingham, AL, and Charleston, SC. 

The timing of leaf-out, migration, flowering and other seasonal phenomena in many species is closely tied to local weather conditions and broad climatic patterns. The Spring Index maps offered by USA-NPN shed light on plant and animal phenology, based on local weather and climate conditions.

How does Punxsutawney Phil's prediction match what we're seeing?

Signs of Spring Map Groundhog day 2018

Punxsutawney Phil predicts six more weeks of winter. We agree - if we're talking about the eastern US. The southeast especially has been cool so far this year. A new forecast by collaborator Toby Ault also calls for an early spring in the west, late in the east. 


Groundhog day spring leaf index 2017 and 2018


The arrival of spring this year is far behind the very early spring of 2017. By this date last year, leaves had emerged all across the southeast and even as far north as Tennessee. This year, spring is arriving far ahead of schedule in Arizona and California.




Spring Indices: Indicators of phenological activity

How do you know when spring has begun? Is it the appearance of the first tiny leaves on the trees, or the first crocus plants peeping through the snow? The Spring Leaf Index is a synthetic measure of these early season events in plants, based on recent temperature conditions. This model allows us to track the progression of spring onset across the country.

The map at right shows locations that have reached the requirements for the Spring Leaf Index model (based on NOAA National Centers for Environmental Prediction Real-Time Mesoscale Analysis temperature products).

Learn more about the Extended Spring Indices and the data products available.

USA-NPN also produces a suite of Accumulated Growing Degree Day map products.

Access Phenology Maps

View a week-by-week animation of the Spring Leaf Index map (Jan 1, 2017-May 15, 2017)

Re-use of Maps and Data

Content, maps and data accessible via are openly and universally available to all users. USA-NPN is not responsible for content or the use of the data. Content may be re-used and modified with appropriate attribution (e.g., "source: USA National Phenology Network,"). See our complete Content Policy and Data Use Policy.

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