Hundreds of thousands of visitors will soon flock to Washington, D.C.’s Tidal Basin to see one of spring’s most-anticipated happenings.

The National Park Service (NPS) announced today peak bloom of the famous Yoshino cherry blossoms will occur March 17-20.

Peak bloom is defined as when 70% of the trees at the Tidal Basin are blossoming. NPS officials say the Yoshino cherry trees are currently in the first of six stages of growth. The trees reached this first stage, the green bud stage, on February 25. Typically, the green bud stage doesn’t occur until early March. Peak bloom occurs in the sixth stage of growth.

Officials last year predicted peak bloom to happen March 14-17, but an unusual cold snap in early March delayed peak bloom to March 25. Peak bloom in 2016 also occurred on March 25.

Similar looking blossoms have already started to appear near the D.C. War Memorial. NPS officials note the blossoms are from the Japanese flowering apricot tree. These blossoms routinely appear earlier than the Yoshino blooms. The apricot blossoms also feature rounded pedals as opposed to the notched petals of the Yoshino blossoms.

This year’s National Cherry Blossom Festival is slated for March 20 through April 15.