Tornado siren test schedule The Monday test is a manual maintenance check on all the Mechanical & Electronic equipment. Sirens will sound in a cycle of 3-5 minutes, followed by a 10-15 minute break, repeated for the duration of the threat (warning period). During the monthly testing, sirens will sound the "Alert" tone, which is a three-minute continuous blast. ) 4. If unable to test the sirens on the second Wednesday, the testing is cancelled until the following month. April thru October / First Wednesday of each month at 12:05 PM; Steady tone of 2 minutes; Sirens are not tested when inclement weather is being experienced within the County. The siren test will occur for a one (1) minute test to ensure that the sirens are functioning properly. Tests are the second Wednesday of the month at 11:00am, but the City and County of Denver will occasionally do additional testing on other dates and times. When activated, the sirens will sound for 3 minutes. Indiana University faculty, staff and students are encouraged to participate in the test. yxqvixlspmdyzqltpkofxezmmgtmwnvdrimoinipusvkvjwvajwgwrnlrkvijpcjehjanqqnuzkwujwvocf