According to the CDC, about 100 people are killed in this country each year by lightning strikes. About 300 more people are injured by lightning strikes.

Drowning and injuries associated with flooding are the top cause of weather-related deaths, the CDC says.

Just before a thunderstorm, the air fills with negatively charged ions. Many people report feeling relaxed, energized, or just plain good. Scientific studies tend to support the existence of this phenomenon. Conversely, exposure to positively charged ions, produced under certain weather conditions, may be associated with increases in industrial and automobile accidents, suicides, and crime, as well as depression and irritability.

Starting when a person in his or her 60s, the body becomes less able to regulate its temperature, the CDC says. The problem increases with increasing age. This makes the elderly very susceptible to prolonged periods of high environmental temperatures. In fact, heat stroke rates may be up to 12 times higher for those over 65 than for those under 65. Young children also are more likely to have problems from a prolonged heat wave, but less so than the elderly.

Many conditions can contribute to an increased risk for heat stroke. For instance, the use of cocaine is implicated in increased risk for heat stroke. Medications that increase the risk of heat stroke include psychotropics, drugs used to treat Parkinson's disease, tranquilizers, antihistamines, calcium channel blockers, beta blockers, certain antidepressants, and diuretics, the CDC says. Race, socioeconomic status, and the presence of social isolation also contribute. The biggest factor against developing heat stroke is a functioning air conditioner.

There is an increase in the expected heart attack rate after snowstorms, and this has been attributed to snow shoveling, the CDC says. Interestingly, many of these heart attacks may occur in people who did not appear to have any pre-existing heart disease. Cold temperatures may slightly increase the risk, but temperature is not as significant as shoveling snow.

The effect is not one to worry about (it doesn't cause medical problems), but it does exist. There is an increased onset of labor in the hours during and just after a drop in barometric pressure. This is seen in hospitals, where increased numbers of women are admitted for delivery during and following a rainstorm or snowstorm.

Increases in smog and, in particular, ozone can bring on asthma attacks in sensitive people.

Remaining indoors during smog and ozone alerts decreases exposure. Avoiding exercise cuts the demands made on the heart and lungs so they don't have to move as much contaminated air. Adults with chronic heart and lung conditions should always heed air pollution alerts.