RICHLAND COUNTY — Mother Nature has turned on the heat in north central Ohio and hot and humid weather will persist at least through the end of the week.

Take precautions to stay cool and hydrated. Here are some terms to be aware when following summer weather forecasts. This information is courtesy of Richland Public Health.

Heat Index — The air temperature can actually feel hotter than what the thermometer reads. The Heat Index is a measure of how hot it really feels when relative humidity is factored in.

Excessive Heat Warning — Take action! An Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this Warning is when the maximum heat index temperature is expected to be 105 degrees or higher for at least 2 days and night time air temperatures will not drop below 75 degrees; however, these criteria vary across the country, especially for areas not used to extreme heat conditions. If you don’t take precautions immediately when conditions are extreme, you may become seriously ill or even die.

Excessive Heat Watches — Be prepared! Heat watches are issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. A Watch is used when the risk of a heat wave has increased but its occurrence and timing is still uncertain.

Heat Advisory — Take action! A Heat Advisory is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this Advisory is when the maximum heat index temperature is expected to be 100° or higher for at least 2 days, and night time air temperatures will not drop below 75°; however, these criteria vary across the country, especially for areas that are not used to dangerous heat conditions. Take precautions to avoid heat illness. If you don’t take precautions, you may become seriously ill or even die.

Excessive Heat Outlooks are issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to those who need considerable lead time to prepare for the event.

A heat wave is when abnormally hot weather lastsat least two days.

How to Respond to Excessive Heat Events

Slow down. Reduce, eliminate or reschedule strenuous activities until the coolest time of the day. Children, seniors and anyone with health problems should stay in the coolest available place, not necessarily indoors.

Dress for summer. Wear lightweight, loose-fitting, light-colored clothing to reflect heat and sunlight.

Eat light, cool, easy-to-digest foods such as fruit or salads. If you pack food, put it in a cooler or carry an ice pack. Don’t leave it sitting in the sun. Meats and dairy products can spoil quickly in hot weather.

Drink plenty of water (not very cold), non-alcoholic and decaffeinated fluids, even if you don’t feel thirsty. If you on a fluid restrictive diet or have a problem with fluid retention, consult a physician before increasing consumption of fluids.

Use air conditioners or spend time in air-conditioned locations such as malls and libraries.

Use portable electric fans to exhaust hot air from rooms or draw in cooler air.

Do not direct the flow of portable electric fans toward yourself when room temperature is hotter than 90°F. The dry blowing air will dehydrate you faster, endangering your health.

Minimize direct exposure to the sun. Sunburn reduces your body’s ability to dissipate heat.

Take a cool bath or shower.

Do not take salt tablets unless specified by a physician.

Check on older, sick, or frail people who may need help responding to the heat. Each year, dozens of children and untold numbers of pets left in parked vehicles die from Keep your children, disabled adults, and pets safe during tumultuous heat waves.

Don’t leave valuable electronic equipment, such as cell phones and GPS units, sitting in hot cars.

Make sure rooms are well vented if you are using volatile chemicals.