My guess is there’s some commonly used component amongst all manufacturers (a 555 chip or something similar) that for some reason it’s easier that way. I don’t imagine it’s some de jure standard agreed upon by the World Wide Clock Makers Consortium.
Wouldn’t it be a great feature if a clock provided a variable setting, or the ability to disable the snooze button? Or are there such models available?
But then that country song would have to be renamed “Another Variable Number of minutes as Desired” Rather than the more catchy “Another Nine Minutes”
They do actually make clocks now that you can select the length of snooze. I was looking at some a few weeks ago.
They were in the $10-$20 price range, not even the really expensive ones.
Sorry, Unca Cece, but even the most likely of your explanations seems unlikely to me. There are so many manufacturers that, even if the clock gods revealed their divine will to one maker, by what mechanism did he successfully prosethelyze to the others? I suspect the 2[sup]9[/sup] is likely true, as it sounds very close to computer style thinking.
Does anyone know for sure?
My alarm clock allows me to do that. I can change the snooze in one minute intrevals from 1 to 30 minutes. The default is 9.
My current alarm clock has an adjustable snooze button, from 1 minute up to an hour. The best part though is the Grad-U-Wake feature, the alarm starts off faint and gradually gets louder. I thinks it’s made by GE, I paid no more than $15 for it.
my alarm clock is not adjustable, but the snooze interval is seven minutes rathehr than nine
My clock does 8 minutes.
My clock does 7 minutes, but each time I push the snooze button it deducts a minute. So the next time is 6 minutes…snooze button…5 minutes…snooze button…4 minutes. Rinse repeat.
My dad’s theory is that it came from an old Swiss clockmaker who, when his alarm would ring during a really good dream, would scream “NEIN!” 
Mine’s seven minutes, too.
Ours are seven and four.
There is a GE alarm clock I can highly recommend. Something like $10 at Wal-Mart and it has a nap feature, a variable snooze feature, and an alarm that gradually gets louder rather than blaring from the start. I don’t remember how variable the snooze is, because I never use it anyway.
My Sharp alarm clock does 5 minutes.
The math in electronic clocks is done in binary-coded decimal (BCD). Nine minutes difference would be the longest snooze period allowed to only need four bits of storage and a single-digit comparison.
That’s my story and I’m stickin’ with it.
mine’s 8, and my last one was 12
The digital one I have was made in China and it has 5 minutes.
That is not long enough for a snooze…
Heh. If only mine did that. Mine gives up on me if I hit the snooze button too many times. (And no, I’m not turning it off-- you can only do that from a switch on the side.) Being lazy-- which is probably why I use the damn thing so much in the first place-- I’ve never counted how many grumpy swats it will take before it deems me a lost cause but it’s too few for my taste.
The clock Knows Too Much. It set itself to the correct time when I plugged it in after removing it from the carton, and even set the alarm for me. For seven thirty, coincidentally enough the time I had to get up the next morning. Yeah, I know that seven-thirty is probably the time when most people have to get up, but sheesh-- I expect the thing to start lecturing me about staying up too late.