The first colors are beginning to show in the higher elevations of the Great Smoky Mountains National Park, which is a popular draw for tourists in October.
Expect a good show, said Janet Rock, a botanist in the Smokies.
"As long as we stay on track with the weather we've had, it should be a good year," said Rock.
The shorter span of sunlight each day is the main trigger, but Rock said temperatures and precipitation also affect the show.
"When you have warm sunny days and nights that don't reach freezing, it brings out the best colors, Rock said.
The mountains weren't badly affected by drought conditions that burned crops to the west.
Leaves change color because they're shutting down photosynthesis, which makes food for the trees. The production of green chlorophyll masks other colors. However, red pigment production also ramps up as photosynthesis shuts down.
Here's the fall foliage outlook for seven states in the Appalachian Mountain region.
GEORGIA: DOGWOODS VIVID
The north Georgia mountains typically showcase some of the state's brightest fall colors, and this year will be no exception, state forestry officials say.
Dogwood and maple trees in the upper elevations have already begun to change color, Ken Masten, a district manager with the Georgia Forestry Commission, wrote in a recent report.
"If we get a cold snap in the next two weeks or so where it gets 15 or 20 degrees colder, then the colors will be a little more vivid," said Joe Burgess, a senior forester with the Georgia Forestry Commission.
The colors are a big draw in north Georgia's mountain towns, where tourists come to see the hues of the leaves and then stay to shop or catch some live music at venues such as the Crimson Moon Cafe in Dahlonega, a town 60 miles north of Atlanta.
KENTUCKY: HOPE FOR RED
The mountainous areas of eastern Kentucky typically put on the best fall color show in the state, thanks to the variety of species and dense canopy. The first color transformations of the season are happening on dogwoods, sourgums and tulip poplars, which are showing yellows.
"I think we can always count on a fair degree of color in Kentucky, especially in the east, because of this envious mix of trees that we have," said Dean Henson, naturalist at Pine Mountain State Park in southeastern Kentucky. He said the forests there have up to 35 species of leaf-dropping trees.
The dry summer hasn't hurt the state's prospects for a colorful fall, but the weather over the next two weeks will determine if the most desirable colors—the reds and purples—come out this year, Henson said.
NORTH CAROLINA: STARTING TO SHOW
The Blue Ridge Mountains are famous for showing their true colors each fall, drawing visitors from around the globe. And with dry summer days soon to be followed by cool summer nights, those bright colors may be coming sooner.
North Carolina's foliage season starts in earnest in the high mountain areas in October and runs through mid-November, with colors cascading down to lower elevations throughout the month. In the highest areas, sourwoods are turning red, while maples are changes to shades of yellow, orange and red. High bush blueberries are turning a deep red, while sassafras is starting to turn its usual mixture of the same colors.
"Following one of the hottest summers on record, the North Carolina Piedmont is looking forward to a beautiful fall season," says Dick Thomas of the Piedmont Environmental Center.
SOUTH CAROLINA: EARLY START
The drought that has dried up the state for much of the summer means that South Carolina's fall foliage will be vibrant—and early—this year.
Blackgum, flowering dogwood, sourwood and sweetgum trees are already beginning to display shades from yellow to orange and bright red. But some of those same trees are already starting to drop their leaves, due to dry conditions.
"The limited summer rains came just in time," said Victor Shelburne, professor emeritus of forestry and natural resources at Clemson University. "While we're still in a drought, we received enough rain to keep most of the leaves on the trees."
Colors are expected to be most brilliant around mid-October in the higher elevations, late October in the lower elevations and early November in the Piedmont.
TENNESSEE: COLOR TEASING
Smokies spokeswoman Molly Schroar noted yellow birch, American beech, mountain maple and hobblebush have begun turning high in the mountains, giving a hint of the rich show to come. But Shroar suggested looking down now and then, to see black-eyed Susans, purple asters, goldenrod and other fall flowers just hitting their peak.
"We're getting teased a little bit by Mother Nature now," said Cindy Dupree of the Tennessee Department of Tourism as she looked out her car window at hits of red sumac and golds in the maples. "It won't be long until it's spectacular."
"On down in the Chattanooga area, that gets just as pretty as I've seen anywhere," Dupree said.
VIRGINIA: ABUNDANCE OF COLOR
With terrain varying from the mountains to the coast, Virginia offers an array of hues for leaf-peepers as 15 million acres of foliage change colors.
Expect yellow and maroon on ash trees, scarlet to purple on the state's dogwoods, and golden bronze on hickories. Virginia's red maples offer brilliant scarlet colors, beech trees feature yellow to orange leaves, poplars present a golden yellow, and reds, browns and russet colors from the state's oaks.
"This year should be a spectacular year because of the summer weather conditions," said Richard Lewis, a spokesman from the Virginia Tourism Corporation. "It's going to produce a lot of very vivid foliage.
Peak colors are expected in the western mountains during mid-to-late October and in the central and eastern parts of Virginia during late October and early November.
WEST VIRGINIA: BEST STILL AHEAD
With most of West Virginia's best fall colors yet to arrive, the best places to see an array of red, yellow and orange are in the highest elevations.
The Division of Forestry recommends drives from Harman to Spruce Knob, from Webster Springs to Valley Head, the Highland Scenic Highway in Pocahontas County, and in the Monongahela National Forest along state Routes 28-55 to the Dolly Sods Wilderness.
With a wide variety of trees and elevations, West Virginia's fall color season began in late September and runs through late October.
Maple, gum, ash, beech and birch trees in higher elevations are showing a mix of colors.
"We are at a higher elevation so we enjoy the leaf color change earlier," said Babcock State Park Superintendent Kevin Cochran. "It's just tremendous here."
Rock, the Smokies botanist, cautioned about planning a leaf-viewing trip too early.
"People seem to jump the gun a lot, thinking Oct. 1 comes and is a magic date."
Rock said the show can last into November, barring storms that bring down the leaves.
Asked when she would take her hike, Rock replied the second to third week of October.
Associated Press writers Michael Felberbaum in Richmond, Va.; Meg Kinnard in Columbia, S.C.; Dylan Lovan in Louisville, Ky.; Jeff Martin in Atlanta and John Raby in Charleston, W.Va. contributed to this report.