Ohio’s tornado season is considered to be April through June, according to the National Weather Service. However, tornadoes can and have happened in every month of the year.

Ohio averages 21 tornadoes a year, calculated from 30 years’ worth of data, the weather service said. Tornado season typically peaks in June and trails off into the fall.

As the area enters peak tornado season, it’s a good time to review what you need to know. What is a tornado watch? How is that different from a tornado warning?

Wondering what these terms mean and when to take cover? Here’s what to know.

What does a tornado watch mean?

A tornado watch means “be prepared.” Tornadoes are possible in and near the watch area. Review and discuss your emergency plans and check supplies and your safe room. Be ready to act quickly if a warning is issued or you suspect a tornado is approaching.

Watches are issued by the Storm Prediction Center for counties where tornadoes may occur. The watch area is typically large, covering numerous counties or even states.

A tornado watch is issued when severe thunderstorms and tornadoes are possible in and near the watch area. This doesn’t mean they will occur.

What is a tornado warning?

 A tornado warning means “take action now” as a tornado has been sighted or is indicated by weather radar. There is imminent danger to life and property. Move to an interior room on the lowest floor of a sturdy building. Avoid windows.

If in a mobile home, a vehicle, or outdoors, move to the closest substantial shelter and protect yourself from flying debris.

Your local forecast office issues warnings. Warnings typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a tornado identified by a forecaster on radar or by a trained spotter/law enforcement who is watching the storm.

What is a severe thunderstorm?

The National Weather Service defines severe thunderstorms as having winds of 58 miles per hour or higher, and/or hail that is at least one inch in diameter.

What does a severe thunderstorm warning mean?

This warning is issued when severe thunderstorms are occurring or imminent in the warning area.

What is a severe thunderstorm watch?

A severe thunderstorm watch means a severe thunderstorm is possible in and near the watch area.

How to stay safe in severe weather

In the event of a tornado, here are some tornado safety rules from the National Weather Service to keep you and your family safe:

• Tornadoes could be obscured by rainfall or come at nighttime. Do not wait until you see or hear the tornado, it may be too late.
• In general, get as low as you can. A basement below ground level or the lowest floor of a building offers the greatest safety. Put as many walls between yourself and the outside as possible. Avoid windows.
• Do not waste time opening or closing windows and doors. It will not protect the structure. You will only waste time and put yourself and others in greater risk. Use those valuable seconds to find a place of safety.
• In homes or public buildings: go to the basement or a small interior room, such as a closet, bathroom or an interior hall on the lowest level. Close all doors to the hallway for greater protection. If possible, get under something sturdy like a heavy table. Protect yourself from flying debris with pillows, heavy coats, blankets or quilts. Use bicycle or motorcycle helmets to protect your head.
• In mobile homes: leave well in advance of the approaching severe weather and go to a strong building. If there is no shelter nearby, get into the nearest ditch, low spot or underground culvert. Lie flat, covering your head with your hands for protection.
• In vehicles or outdoors: when tornadoes are possible, limit your outdoor plans or finish them early. Stay close to a sturdy shelter. If caught outside, find shelter in a ditch or remain in your vehicle and cover your head for protection. Do not take shelter under a highway overpass, where wind speeds can increase due to a tunneling effect. It is best to not put yourself or others in a situation where no sturdy shelter is available.
• Stay away from doors, windows, outside walls and protect your head!