"In some areas in the United States, civil defense sirens may sound in the late morning and early afternoon on a regular basis. In places like Haxtun, Colorado the siren goes off at 7 a.m., noon, 1 p.m., and 6 p.m. everyday except Sunday, to signal the time."
I was in Mobridge, South Dakota for vacation this summer visiting my family up there, and every night near, or around 10 PM, a FS 2001 that's not far from my stepmom's house goes off for a 30 second blast to tell all the children that it's time for Curfew. They also have another siren in town that's probably most likely used for calling out volunteer firefighters, in addition to probably warning Mobridge about Tornado warnings. I heard that siren many times when I was on vacation (not the one by the fire department), and it was not only a great use for a curfew signal, I thought it was cool that city sounded that single siren to let every kid know that it's time to go inside. I never did hear the fire department siren go off for any fire calls. I think they test all the sirens at least twice a year, and citizens are warned ahead of time.
I should mention that the following fact is a little off topic from what I said above: Mobridge, South Dakota is such a small town, it's easy to find everything in town, and you can't get lost. I can walk down the street from my stepmom's house, and be in downtown Mobridge in about 10 to 15 minutes!
