If there are two things the District does well — aside from half-smokes and traffic congestion — it’s spring flowers and unpredictable weather.
On Monday, that unusual paring teamed up as part of a bewildering forecast that predicted an on-schedule blooming period for the city’s beloved cherry blossoms this month, even as meteorologists warned of a midweek storm that could dump 5 inches of snow or more on the area.
The peak bloom time for the 1,678 trees around the Tidal Basin is forecast between March 26 and 30, National Park Service officials said, meaning for the 12th year in a row the blooms will blossom during the National Cherry Blossom Festival.
The announcement was made at the Newseum, where the five-story atrium was decked out in pink hues familiar to the blossom celebration.
The trees normally bloom between late March and early April, though extreme hot or cold temperatures have caused blooms as early as March 15 and as late as April 18. Mr. Perry said the blossoms have lasted as long as 18 days and as short as five days.
The peak bloom time is the period during which 70 percent or more of the blooms have opened. Precise days when the blooms will be at their most glorious are forecast later in the month, though Mr. Perry said that normally comes closer to the end of the blooming period.
“Mother Nature decides that,” he said.
March can be somewhat of a roller coaster of weather patterns, officials said, but unlike last year, which was warm enough to require the Park Service to bump up its predictions by a week, the monthly outlook for this March is not as easy to predict.
National Weather Service science and operations officer Steve Zubrick said “the odds of going either way are kind of equal” for whether March could be unseasonably warm or cold.
The average high for March in the District is 55.9 degrees, while the average low is 37.6 degrees. Last year, the average temperature was about 10 degrees warmer, which coaxed the blossoms out of their buds on March 20. The average peak bloom date is April 4.
The warmest day in March on record was March 23, 1907, when it was 93 degrees. The coldest day in March was March 4, 1873, when it was just 4 degrees above zero, according to the Weather Service.
“In March we can certainly have some very warm and some very cold days,” Mr. Zubrick said, adding that the District is looking at a forecast that could bring several inches of snow on Wednesday.
While the blossoms are still buds, they are mostly protected from the elements, not unlike flowers kept in a florist’s refrigerator.
Snow can be a threat once the blossoms open, however, but in general “they can handle a couple days of not great weather,” Mr. Perry said.