Will the Cherry Blossoms ever bloom? We expect additional delays

With the recent snow and record cold, cherry blossoms are probably the last thing on people’s minds. But, the weather pattern is about to turn the corner and next week looks springlike! That will give the blossoms a friendly nudge. Still – given the recent unseasonable chill – we are pushing back our forecast for the cherry blossom’s peak bloom several days from around April 9, to April 13.

Earlier this month, we predicted a peak cherry blossom bloom date of around April 9 – about 5 days later than normal – due to our expectation for colder than average temperatures into early April. Well, it’s been even a little colder than we expected. We projected March would end up about 2.5 degrees below normal but now it seems like it will close around 4 degrees colder than the norm.

bloom-chart

For reference, last March finished 3 degrees colder than normal and peak bloom occurred on April 9. So if March temperatures are a key predictor of bloom dates, we would expect this year’s bloom date to be later than last year.

In fact, this year’s bud development is trailing last year’s by 6 days according to the National Park Service. In 2013, florets became visible on the cherry trees on March 17; this year, that milestone wasn’t reached until March 23. The Park Service says peak bloom typically occurs around 16-21 days after florets become visible. If that’s the case this year, we’d see peak bloom between April 8 and April 13. So it’s possible the peak bloom could still occur around April 9, and within the original April 7-11 bloom window we said was most likely.

But when you consider last year it took 23 days for peak bloom to occur after the florets were visible, that might suggest this year’s peak bloom could be delayed until April 15.

Working in favor of an acceleration in this year’s bud development is the warmer weather expected next week. We should have several days with highs in the 60s to near 70. On the other hand, cooler than normal weather may return next weekend and we don’t see any of the 80-degree weather which gave the blossoms a final big push between April 6 and 9 last year.

A view of the Tidal Basin and blossoms from above, April 1, 2010. (Kevin Ambrose)

A view of the Tidal Basin and blossoms from above, April 1, 2010. (Kevin Ambrose)

When we released our blossom peak bloom forecast on March 6, we said: “If we’re wrong about the peak bloom period, we think it’s more likely to occur later than earlier than our predicted range.”

Considering all available information, I’m revising our peak bloom forecast four days later to between April 11 and April 15, centered on April 13.

Here are revised peak bloom period probabilities:

Peak bloom April 11-15: 60 percent chance (most likely)
Peak bloom April 6-10: 20 percent chance
Peak bloom April 16-20: 15 percent chance
Peak bloom outside of the above ranges (April 6-20): 5 percent chance

Note: The National Park Service’s bloom prediction remains between April 8 and 12, centered on April 10.

Frequent questions:

Has the recent snow and cold harmed the blossoms? No. Snow will not damage blossoms unless it is heavy and wet enough to cause damage to their tree limbs. Temperatures need to be in teens or colder to damage the blossoms. They have not been that cold at the Tidal Basin.

Is cool weather actually a good thing for the blossoms? Yes. Cool weather tends to extend the blossoms’ bloom period as it slows down the opening of the flowers. Warm, sunny weather can cause the buds to burst quickly, limiting the period of peak bloom.

Related content:

DC blooms: Where to find cherry blossoms in your neighborhood.

2013 cherry blossom coverage

Ten days of cherry blossoms (PHOTOS, 2012)
Cherry blossoms bursting out (PHOTOS, 2012)
Cherry blossoms with an overcast sky (PHOTOS, 2011)
Washington’s cherry blossoms in the snow (PHOTOS, 2011)
A cherry blossom bird’s-eye view (PHOTOS, 2010)
Cherry Blossoms Wind Down as D.C. Greens Up (PHOTOS, 2009)
Cherry Blossom Morning (PHOTOS 2009)
Washington D.C.’s Cherry Blossom Bloom Begins (PHOTOS, 2009)
Photography: Falling Blossoms & Spring Scenes, Kevin Ambrose (2008)
Photography: A Blooming Good Time (2008)
Photography: Glorious Cherry Blossom Sunrise (2008)
Photography: Cherry Blossoms by Night (2008)
Photography: Flying High as Spring Blossoms (2008)

Also on Capital Weather Gang

The long, white 2013-2014 winter: Bringing snowy back to the D.C. region (season statistics)