How did the unusually snowy winter in Washington, D.C. affect the timing of blooms on the city's famed cherry trees? The annual Cherry Blossom Festival is now underway, along with the guessing game about the period of peak blooms. What do the experts say about the best time to view the blossoms in 2010?

The dubious honor of predicting "peak blooming dates" for the trees falls to Horticulturist Rob Defeo and other staff members at the NPS' National Mall and Memorial Parks. They have data from plenty of previous years, and know that while the average peak bloom date is April 4, the best of the flowers has arrived as early as March 15 and as late as April 18. Even so, averages are just that, and each year offers a new challenge for the floral prognosticators.

So, did the fierce winter and deep snows earlier this year delay the blooms this spring?

Initial predictions were for an April 3-8 peak, but Mother Nature offered up a warm spell that shifted those dates to April 1-4. Now the timing for the predicted peak blooms has been updated to include just two days this week: April 1-2.

That puts the height of the blooms a bit ahead of the statistical average, but there should be plenty of beauty to enjoy before and after those dates. The overall blooming period is now expected to last until about April 8, although that can be affected by factors such as heavy rain or high winds.

What does the "peak blooming period" mean, anyway? According to a website for the National Cherry Blossom Festival,,

Exactly when the buds will open is not an easy question to answer. It is pretty much impossible to give an accurate forecast much more than 10 days before the peak bloom. National Park Service Horticulturists monitor 5 distinct stages of bud development and provide forecasts and updates as needed.

The Peak Bloom Date is defined as the day in which 70 percent of the blossoms of the Yoshino Cherry (Prunus x yedoensis) trees that surround the Tidal Basin are open.

The famous trees, a gift from Japan in 1912, signal Washington’s rite of spring with an explosion of life and color that surrounds the Tidal Basin in a sea of pale pink and white blossoms. Thousands of city residents and visitors from across the nation and around the world come here to witness the spectacle, hoping that the trees will be at the peak of bloom for the Cherry Blossom Festival.

The NPS is offering some special activities during the annual festival, which runs from March 27-April 11 this year. They include:

Interpretive Cherry Blossom Talks "relate the cultural and natural stories behind these national treasures. Story topics range from the arrival of the cherry trees in Washington, D.C., to the "Cherry Tree Rebellion" that placed the construction of the Thomas Jefferson Memorial in jeopardy, to the varieties of cherry trees that grow throughout the park."

The free, 30-minute programs are offered at the Thomas Jefferson Memorial welcome tent and the Franklin Delano Roosevelt Memorial at 11:00 a.m., 1:00 p.m., 3:00 p.m. and 5:00 p.m. each day through April 11.

Ranger Guided Lantern Walks will be available from 8:00 p.m. to 10:00 p.m. through April 11. Participants should meet near the Welcome Tent at the Tidal Basin Paddle Boat Area.

Led by National Park Service rangers, these FREE evening walks bring new perspectives to the story of the cherry trees. Soft light turns to darkness along the Tidal Basin, during these strolls through the annual glory of the blooming of the cherry trees. Follow the history of these precious resources on this two-hour,1.5-mile long walking tour around the Tidal Basin. Please wear comfortable shoes and bring your own flashlight.

You can download a map showing these locations around the National Mall at this link.

In addition to special activities in the park, the National Cherry Blossom Festival includes a wide variety of events through April 11th. Highlights include a fireworks display on Saturday, April 3, and a parade and Japanese Street Festival on Saturday, April 10. You'll find a complete list of eventson the Festival website.

Predicting the exact dates for blooms may be a challenge even for the experts, but there's not much debate about another key factor for anyone intent on seeing the flowers—and enjoying the experience. The secret: don't try to drive your car right to the Tidal Basin and expect a leisurely trip and a short search for a place to park.

The Festival website notes,

Transit, walking and biking are the best ways to see the blossoms, but if driving is your only option, plan ahead to minimize your time in congested traffic. Commercial parking lots are available with links to transit and the Mall. Some commercial parking is available within walking distance. There is a high demand for parking within the blossom area. Utilize this routing information to avoid the worst bottlenecks during peak blossom times. That link also includes metro maps, DC Circulator Bus Routes and Stops, Tour Bus Parking information, and tips for driving, parking and the "Fastest Taxi Route to the Blossoms."

The weather is a big factor not only for determining the dates of blooms, but also in the size of the crowds. After a rainy start to the last week in March, the weather is predicted to improve to the "outstanding" category for the first few days in April. Like all prudent visitors, you'll check for weather updates before heading out to enjoy the trees.