ROCKFORD, Ill. (WTVO) —When the threat of severe weather occurs, it’s important to know the difference between a watch and a warning.

A Watch means severe weather is possible and conditions in the atmosphere are favorable for severe weather, but it’s not occurring yet. You need to remain alert for quickly changing weather conditions. A severe thunderstorm watch or tornado watch is often times issued hours in advance of potential severe weather.

A Warning means severe weather is either going to occur or is occurring already, in your area and you need to take shelter immediately – take action. Sometimes these can be issued 20 minutes before the storm arrives or only a few minutes before the storm moves in.

Climatologically, the months of April, May, and June are our peak severe weather seasons in northern Illinois, with the most tornadoes reported during that three-month period. However, tornadoes can occur during any month and that’s why it’s so important to have a severe weather plan in place.