In my climate zone , the New York area, I prefer not to direct seed this late in the season [It's late September] but start from young plants in peat pots for a harvest in early spring. Transplanting can cause forked and curved carrot roots using peat pots helps avoid this.
In warmer regions where the ground does not freeze all that much, carrots can be planted right up through Halloween. In areas that experience heavy snow cover for long periods of timeYou'll want to heavily mulch the carrot beds with organic mulch such as leaves, hay or bark to prevent the tops from dieing back.
Raised Beds warm up faster in spring, they will also retain more warmth later in the season than planting directly on the ground does. If you have them are awesome, the elevated soil of raised beds will not freeze as readily as ground soil.