Decoding Weather Health Warnings

People with allergies will feel symptoms when the count tips into the yellow range.

Because pollen counts are highest from 2 a.m. to 10 a.m., don't sleep with your windows open, advises Dr. Pamela A. Georgeson, president of Kenwood Allergy and Asthma Center in Chesterfield Township, Michigan. Run the air conditioner to filter allergens. Before bed, take a shower to remove pollen that may be sticking to you.

AQI is a composite of five pollutants, including ground-level ozone. It's keyed to a number from 0 to 500 and a color chart: green, yellow, orange, and red.

Some doctors may suggest taking an extra dose of medication on high days, but you should check with yours to see if that's a good idea.

When the UV outlook reaches the high levels of 6 to 7, alerts go out. However, if you have fair skin, your potential for burn begins even in the moderate range, notes Dr. Mary P. Lupo, a dermatologist in New Orleans.

The heat index measures how hot it feels based on air temperature and moisture in the air. It has four warning levels: caution, extreme caution, danger, and extreme danger.

The heat index is usually highest between 4 and 5 p.m.

Drink fluids, even if you don't feel thirsty. If you plan on being outside doing strenuous activity, do it when the index is lowest, usually early in the morning around sunrise.