Spring is springing earlier and earlier

With yet another winter storm set to batter the Northeast this March, many residents might disagree, but Tuesday really is the first day of spring.

And in large expanses of the continental United States, spring is actually arriving earlier than in past years.

The USA National Phenology Network monitors the status of spring in the form of first-leaf and first-bloom indexes.

First-leaf dates vary annually, but earlier first-leaf dates appear more prevalent within the last few decades. With the exception of the Southeast, most of the continental United States is experiencing a shift toward earlier springs.

Two-thirds of the United States is expected to be warmer than average this spring, according to the National Oceanic and Atmospheric Administration Spring Outlook.

“The long-term trend does favor above-normal temperatures during April, May and June for a large part of the country, generally stretching from the Southwest U.S. east-northeastward to include the south-central Plains, Southeast, Ohio Valley, Mid-Atlantic (D.C.) and the Northeast U.S.,” said NOAA seasonal forecaster Jon Gottschalck. “The colder-than-normal conditions being seen in March do not necessarily connect and spell an outcome of a cold spring in any way.”

The two indicator species used for first-leaf dates are lilacs and honeysuckles, as they have a large geographic distribution, a high survival rate and have an easily monitored flowering season.

The timing of spring varies year to year. However, some years stand out as particularly early springs, notably the spring of 2012.

Most of the continental United States experienced its highest springtime average temperature in 2012, according to a NOAA National Climate Report published last month, and a large portion of the continental United States has experienced its highest average spring temperature in the past seven years.

As spring approaches, so does cherry blossom season in Washington, D.C.

While this year’s peak bloom date for cherry blossoms in the District was pushed back a week to April 1 because of cold weather, the long-term trend indicates the peak bloom date has moved up in the calendar by approximately five days since the 1920s.