A man died in Howard County in June, Maryland’s first heat-related death this season, Maryland’s Department of Health and Mental Hygiene reported Wednesday.

The man was between 45 and 64 years old and had underlying health conditions, health officials said in a news release.

High temperatures are responsible for the highest number of weather-related fatalities , outpacing floods, tornadoes, hurricanes and other events, according to the National Weather Service.

An average of 618 deaths every year between 1999 and 2010 were associated with exposure to excessive natural heat, according to the Centers for Disease Control and Prevention.

Groups at the greatest risk for heat-related illness include infants and young children, youth athletes, people 65 and older and people with certain medical conditions, including mental illness, diabetes and hypertension, officials said.

Residents should stay in air-conditioned buildings as much as possible, drink more water than usual, and avoid drinks with caffeine, alcohol and large amounts of sugar.

The health department advises that residents should also be aware of the symptoms of heat-related illnesses including:

Heat cramps: These are short, severe cramps in the muscles of the leg, arm or abdomen that can happen during or after heavy exercise in extreme heat. Heat cramps also may be a symptom of heat exhaustion.

Heat stroke: The most serious heat-related illness, heat stroke occurs when the body’s temperature rises too rapidly — to as much as 106 degrees Fahrenheit or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not provided. Symptoms of heat stroke include red, hot and dry skin, no sweating and a rapid, weak pulse.