There are a couple of different ways to look at what's typical and what the extremes are with Thanksgiving coming up this Thursday. First, we can look at climate data for the specific date that Thanksgiving occurs on this year, which will be the 25th of November.
By that measure, a check of records for the Raleigh-Durham airport shows that over the 62 years of available data in a Southeast Regional Climate Center daily statistics tabulation, the average high for the date has been 58 degrees, with an average low of 36, and we've seen extremes of high temperature ranging from a cold 41 degrees in 1970 to a toasty 79 in 1973. Low temperatures on that date have been as frigid as 11 degrees in 1970 to as balmy as 61 in 2001. In terms of precipitation, we've had as much rain as 1.46" in 1957, and recorded 1.3" of snow in 1962. Keep in mind this is for a specific date, and not all of those records apply directly to Thanksgiving Days, since the date of the holiday is not fixed in the same way as July Fourth, or New Year's Day.
However, the State Climate Office of NC has a neat feature on their web page that works out which date the variable holidays fall on, and sifts through weather information to arrive at some climate info for the holidays themselves. For Thanksgiving, this process was carried out using several cooperative observing sites in the area, but not for the Raleigh-Durham airport. NC State College (and later University) has maintained a site with records since 1892, and a check of records from there for every Thanksgiving Day shows the warmest afternoon was 78 degrees on Nov 28, 1985, while the chilliest high was 41 degrees on Nov 26, 1970, with the greatest amount of precipitation recorded on Nov 26, 1992, when 1.97" of rain fell.
The forecast for this Thanksgiving has been a little tough to pin down with confidence so far, as a pair of fronts affecting the region have been speeding up, slowing down, and varying somewhat in north/south position and intensity with successive projections of the same computer model , and from one modeling system to the next. For now, it appears we'll have a good chance of dry weather but lots of clouds on Thursday, with a small chance of sprinkles and temperatures that top out somewhere in the upper 50s to mid 60s, followed by a better shot at some showers later Thursday night or Friday, then bright skies and chilly temperatures for Saturday and Sunday. Stay tuned, though, for any further changes...