Menu > Parental, Fav's & Setup > System Setup > Display > Move cursor up & across to "Clock" > Daylight (DST) gives choice of "Yes, No or Auto (Yes)".
Auto should work fine, but if it doesn't you can try selecting "Yes" now, and "No" in the Fall.
PS: In Auto, I'd wait til morning to check - it might take some time to take effect.
 I went out to dinner, was having a beer, and thought that it might be your ZIP code being incorrect. - Check it via the Info screen. Post back if you need instructions or PM me.