Raleigh, N.C. — If you plan to watch the ACC Championship game Sunday, don't forget to switch your clock or you’ll be an hour late, wondering why the game began without you.

The annual switch to daylight-saving time is this weekend—but it’s never been this early. This time, thanks to a law passed by Congress, we’re making the change three weeks earlier than we did traditionally. What happens is that at 2 a.m. Sunday, it suddenly becomes 3 a.m.

Moving the date could throw some of your gadgets out of whack.

“This is more an annoyance and not a disaster," says Lance Ulanoff of PC Magazine. Nonetheless, switching on a date other than the first Sunday in April could set off a string of software snafus.

The main impact for consumers will be that some gadgets pre-programmed to make the change in April won't be able to cope.

“Many people have phones that keep their calendars, their appointments. So this becomes more critical," Ulanoff said.

Though service providers say most cell phones and smart phones will automatically update the time, experts say that with smart phones, you'll likely have to update the computer software with which it synchronizes information.

Visit your software providers' Web sites for advice.

Your cable box and most DVRs will update automatically, but you will have to manually change the time on VCRs.

Computers that run Microsoft Windows should be OK, but you will have to manually change the computer’s internal clock if you have an older operating system.

Now if that all seems too much of a hassle, you can just wait three weeks for your gadgets to catch up with the country—and just hope you remember that your times and appointments will be an hour out of kilter in the interim.

If you do need to change your computer's clock manually, keep this in mind. You'll need to do it four times: On Sunday, again in April when the computer sets itself for the old daylight-saving time switch, then twice in the fall. Software companies all have updates you can download.