The symptoms are unmistakable: Wandering thoughts. Uncontrollable urge to be outside. Odd sense of well-being and, daresay, friskiness.
As infectious as it seems, spring fever isn't anything you can actually catch, but it may have some basis in biology.
"People really do get psyched up for springtime," said Dr. Jon Abramowitz, associate chairman of psychology at UNC-Chapel Hill, who recently offered his insights as part of a list of spring health tips.
Abramowitz said people are susceptible to a concurrence of nature — sunshine and warm weather erasing the dark winter — which triggers a genuine mood boost.
"I'm definitely happier," said Deanna Davis, who spent Monday afternoon at Roanoke Park near downtown Raleigh, N.C., with her 3-year-old daughter, Campbell.
Sunshine alone gives many a lift, particularly if they suffer from a form of depression that deepens in the low-light winter months.
And as temperatures rise, outside beckons with long walks, runs, bike rides, Frisbee games, gardening. The extra activity generates endorphins, a natural chemical that works like opium in the brain.
Stoked on sunshine and exercise, people smile. They're relaxed. They look good.
"When you're feeling good, you're more likely to be attracted to others and they're more likely to be attracted to you," Abramowitz said.
And that is spring's most contagious feature.
"This is a time that's very important from a survival of the species perspective for animals to mate," Abramowitz said. "It is in the air."
"That's cool," said Joseph Rumsey, walking with his girlfriend, Allison Gold, in the Raleigh Municipal Rose Garden. "I can see how that works."
And the two stopped to smell the white roses.