AUSTIN (KXAN) — As our temperatures continue to climb and our pollen continues to spike, you may be noticing more and more trees, plants and flowers budding and blooming noticeably earlier than years passed.

The USA-NPN or National Phenology Network monitors the rise in temperatures and the impacts our changing climate has on our plants across the United States. It even has a page solely dedicated to the status of spring across the nation.

Being able to track seasonal and year-to-year changes with our growing seasons can help farmers and the food industries that rely on them. This type of information can also be valuable to local gardeners planting or harvesting at the most appropriate time.

The National Phenology Network’s research has led to the creation of ‘The First Leaf Index’ and ‘The First Bloom Index.’ Data of lilacs and honeysuckles were chosen as the plants/shrubs it tracked to help create these maps. These specific plants were strategically chosen for two reasons:

  • These two combined can be found in nearly every state across the United States.
  • Lilacs and honeysuckles are consistently among the first few plants to grow their leaves at the start of spring (tree leaves sprout much later due to their significantly larger size).

The First Leaf Index is based on the leaf out of lilacs and honeysuckles. Leaf out means the budding or first sprouting of a leaf within a plant.

Spring Leaf Index Anomaly

The first leaf index anomaly shows the red area (earlier than normal) continuing to spread northward each day across the majority of the central and eastern third of the country. Comparing this year’s first leaf date with the 30-year average gives us the anomaly (difference from normal).

Here are some notable points of this season:

Much of Texas saw its first spring leaf of 2023 arrive days to even weeks earlier than average. We are not alone, however. Much of the Mid-Atlantic and Ohio Valley is seeing a huge jump in their start of spring leaves.

As of March 13, one of the earliest locations is Nantucket, Massachusetts, with a whopping 35 days ahead of schedule. The west however is experiencing a mixture of earlier AND later-than-normal start days. Southwest Utah is days to over a week late and Portland, Oregon, is two days late. Much of southern Arizona is off to a very late start as well.

The more-than-likely cause of this has to do with the La Niña weather stronghold on our weather pattern over the winter that brought much of these same areas in red an unseasonably warm and even record-breaking winter.

The First Bloom Index is based on the flowering of the same plants.

Spring Bloom Index Anomaly

The first spring bloom which follows/lags behind the first leaf looks fairly similar. Much of the spring bloom has also arrived earlier than normal in many of the same locations shown in red. The later-than-normal areas are in similar locations as well. With that said, because of the lag in the time of flowers blooming, the red shade has not quite extended as far north in latitude just yet.

Some notables of this season:

  • As of March 13, spring bloom is 10 days late in Las Vegas, Nevada, and 22 days early in Norfolk, Virginia. 

How typical is this spring compared to recent decades?

Here are the maps comparing how rare or often this year’s spring is from decades in the past.

Spring Leaf Index Return Interval

Darker colors represent springs that are unusually early or late in the long-term record. Gray indicates an average spring.

Spring Bloom Index Return Interval

Some major notables:

Much of the Southeast up through the mid-Atlantic and into the New York City area is experiencing a spring that only occurs once every 40 years. A few are even experiencing the earliest spring on record.

As for a late start, portions of Arizona are seeing a spring that only occurs this late once every 40 years.