The cherry blossoms have not progressed much lately, thanks to cool air. (Joe Flood via Flickr)

The cold weather we’ve observed so far in March has slowed down the progress of cherry blossoms toward peak bloom. With cooler-than-normal weather predicted over the next one to two weeks, at least, we’re pushing our original forecast for peak bloom back a week, from March 23 to 27, centered on March 25, to March 30 to April 3, centered on April 1.

The National Park Service also announced Monday afternoon it is pushing back its peak bloom date from the March 17-to-20 window to March 27 to 31.

“While the mathematical models still show the blossom reaching peak on March 18, this week’s cooler than forecast temperatures have necessitated moving the projection to the last week of March,” the Park Service said.

If the blossoms reach peak bloom late in March or the first few days of April, it will come very close to the recent 30-year average of March 31.

After the blossom’s bloom cycle got off to a rapid start in late February, assisted by record 80-degree warmth, temperatures have cooled way down.

Through the first third of March, the average temperature is running close to a degree below normal, and there have been no abnormally warm days.

The cherry blossoms are still advancing through the green bud stage, which they reached Feb. 25, the first of five stages in their development. While they’ve progressed slowly since then and are nearing the “florets visible” stage, they have three additional stages to pass through before arriving at peak bloom:

  • extension of florets
  • peduncle elongations
  • puffy white

The blossoms progress most quickly when days are warm and sunny, in the 60s or warmer, and when nights remain well above freezing. But since March 1, our warmest day has been 59 degrees, and the temperature most nights has sunk to near freezing.

Looking ahead at the next 10 days, the European model forecasts highs mostly in the 40s and 50s. More significantly, nighttime lows are persistently predicted to fall to around freezing or a little colder. All of this means that the progression through stages should continue to be quite slow.


European model 10-day temperature forecast. (WeatherBell.com)

Beyond 10 days, Capital Weather Gang’s long-range forecasting specialist, Matt Rogers, said he predicts that cooler-than-normal weather will continue.

Of course, by late March, the average high temperature rises above 60 degrees. So unless temperatures are much colder than normal, the blossoms should steadily progress through stages.

It’s not out of the question that we would need to revise our date once more. But, for now, around April 1 seems like a reasonable approximation.