As Illinois enters its busiest tornado month of the year, suburban DuPage County is making a big change to its tornado siren ...

CHICAGO (CBS) -- Outdoor warning sirens across Illinois will have their monthly test this Tuesday morning, after they were canceled last week. The state's air-raid sirens are tested the first ...

Sirens are tested on the first Tuesday of each month at 10 a.m. in Illinois. The state uses a single alert siren to signify an emergency alert, such as a severe storm or tornado warning.