Nothing to sneeze at: This year's spring allergy season is shaping up to be a nasal nightmare.

RODALE NEWS, EMMAUS, PA—An unusually cold winter, flooding, and an uncharacteristically hot early spring has resulted in one of the worst spring allergy seasons on record, according to allergy experts. In a short amount of time, "we've gone from extreme cold with a lot of snow cover to very warm weather," explains American College of Allergy, Asthma, and Immunology (ACAAI) spokesman James Sublett, MD, clinical professor and the chief of pediatric allergy at the University of Louisville School of Medicine in Kentucky (a spring allergy hot spot).

The extreme cold late in winter delayed tree blooming a bit, but then the rapid temperature shift early this spring from frigid to unseasonably warm—and even hot—accelerated early grass-pollen production. Add to that the flooding that occurred in some parts of the country, and you've got a recipe for prime, miserable spring allergy conditions.

THE DETAILS: Depending on where you live, spring allergies could be particularly torturous this year. The Asthma and Allergy Foundation of America (AAFA) uses three factors—pollen counts, medicine use (prescription and over-the-counter), and the number of board-certified allergy specialists in the area—to come up with the worst spring allergy areas in the country. This spring, the city with the highest score, Knoxville, Tennessee, was named the spring allergy capital. AAFA considers this the most challenging place to live in the United States for people with spring allergies. Here's the complete top 10 list:

1. Knoxville, TN
2. Louisville, KY
3. Chattanooga, TN
4. Dayton, OH
5. Charlotte, NC
6. Philadelphia, PA
7. Greensboro, NC
8. Jackson, MS
9. St. Louis, MO
10. Wichita, KS