Some might like it hot — but not if you want eye-popping fall foliage.
The ongoing summerlike heat in the Northeast has dulled some of the annual foliage spectacle there, where leaf-peeping typically brings in millions of tourists and hundreds of millions of dollars.
The muted colors have come in a year in which experts had originally predicted the cool, wet summer would produce spectacular October foliage, especially in New England.
But the summer was followed by a very hot, dry September, which allowed the leaves to continue producing the chlorophyll that keeps them green.
Usually, chlorophyll production slows and eventually stops in the fall. Without chlorophyll, the yellow and orange pigments of the leaves become dominant, resulting in the many beautiful colors of fall, the Weather Channel said.
Overall, vibrant fall colors occur when three factors come together: the days get shorter, dry weather prevails, and the temperature drops, according Michael Day, University of Maine research professor of physiological ecology.
While the days got shorter and it's been very dry recently, sustained cool to cold weather hasn't arrived yet.
How hot? It was the third-warmest September on record in Massachusetts, New Hampshire, Rhode Island and Vermont, according to the Northeast Regional Climate Center.
And, unfortunately, the greatest threat to vibrant fall colors across the region is warm weather, according to AccuWeather.
"Tourism is a big part of Vermont's economy, much of it based on our landscape, and fall foliage as it turns out is a big chunk of that," said Michael Snyder, commissioner of Vermont Forests, Parks and Recreation.
Deb Moore, who owns The Foothills Restaurant in Warner, N.H., said she didn't think the subdued color would stop tourists from coming. "I think with the gorgeous weather you can't really complain too much," Moore said.
After a few typically cool days this week in New England, warmer-than-average temperatures are forecast there by the weekend and into next week. In fact, unusual warmth is forecast for most of the next two weeks across the entire eastern half of the nation, the Climate Prediction Center said.
Though not as famed for fall foliage as the Northeast, the Midwest and Southeast can also get their share of fantastic leaf colors.
Northern Michigan has seen a delay in the fall color there: "Due to the unseasonable warm weather, fall colors for Mackinac Island are not expected to peak for at least two more weeks," according to the state's fall color update issued over the weekend.
In the Blue Ridge mountains in the Southeast, the color at high elevations "will not be good this year," according to Blue Ridge Mountain Life's fall foliage page. "There will still be some color that high up, but many of the trees have browned due to the temperature changes." Lower elevations should still see some nice colors, however.
On Sunday and Monday, the remnants of Hurricane Nate brought lots of high winds to the Blue Ridge, which caused another problem: "We saw lots of leaves on the ground as a result," according to Blue Ridge Mountain Life.
Weird in the West
In the Far West, in California's Sierra Nevada, the fall foliage season had its latest start since 2000, according to SFGate. What's also weird there is that lower elevations are peaking before higher elevations, which is the opposite of normal.
"Experienced fall color watchers are at a loss to explain why this has happened. Some believe it is because of last winter's record snow," California Fall Color site manager John Poimiroo told SFGate.
In other parts of the West, the pretty fall colors have been replaced by a blanket of snow, especially in the Rocky Mountains of Montana, Wyoming and Colorado, the Weather Channel said.
Freezing temperatures can quickly put an end to the colorful foliage as they destroy the ability of leaves to manufacture the red and purple pigments.