Warriors have not lost to their capital rivals since January 2011, winning three and drawing one of the four contests that have followed since.
But Townsend is worried their air of superiority could be blown away amid the hustle of the world's oldest club derby.
He told Press Association Sport: "History does not count for much when you are preparing for a game like this. They are always really close games.
"Last year was like that and we just managed to shade the two games but that doesn't mean we can expect to win this one."
While Glasgow have enjoyed the upper hand in their recent meetings, it is Edinburgh who are the side in form right now.
The RaboDirect PRO12 fixture - which doubles as the first leg of the 1872 Cup, with the Scotstoun return to come on New Year's Day - offers Edinburgh the chance to trim back Glasgow's eight-point lead in fifth place.
The hosts have triumphed in five of their last seven games, while Townsend is facing up to his toughest spell as Glasgow boss since taking over last year.
His side suffered back-to-back defeats against Cardiff Blues in the Heineken Cup this month, while league defeats to Newport Gwent Dragons and Munster in recent weeks, combined with Friday's postponed clash against Treviso, have seen them slip down the table.
Skipper Alastair Kellock has also been ruled out for four months with an arm injury b ut the Scotstoun head coach is refusing to panic just yet.
Townsend said: "We've lost our last two games and that is not good enough. We've had opportunities to win both those games so we have worked hard to rectify that.
"But we've won two or three more games this year than we had at the same stage last season so we've got a lot to build on.
"Edinburgh will be full of confidence. They have had some really good results in recent weeks but we are itching to get back out there after the Treviso game was called off.
"You can see that there is a massive game coming up just from the way the boys have been training. Everyone is desperate to be involved."
Glasgow started the season with a bang as five straight wins took them to the top of the PRO12 standings.
Their early displays were hallmarked by a watertight defence but their attack has lacked the same intensity and the 14 tries registered so far is well short of the 21 notched up by leaders Munster.
That has cost them vital bonus points - they have picked up just one so far - but Townsend is only focusing on putting wins on the board.
"Bonus points are one thing but we have also dropped down the table because we didn't play at the weekend and a couple of teams around us played and won," he said.
"For me, it's about winning games. If you are lucky enough to get a dry day and things go well, then you can look for bonus points. But I'd rather focus on improving the performances so we keep winning games."
The Boxing Day derby comes just a month before Scotland boss Scott Johnson will send his side out for the RBS 6 Nations opener against Ireland.
And Townsend said players from both sides will be eager to put down a marker for the Dublin clash.
"It's in the back of the lads' minds, especially for the guys who have a one-on-one battle against their direct rival," he said.
"So whether we go with Chris Cusiter or Henry Pyrgos, they know if they play well against Greig Laidlaw, they have a better chance of being selected for the Six Nations. It's the same for a lot of the other lads.
"But at the end of the day, it's two teams playing for league points and these are crucial games. The guys will be running out in front of the biggest crowds we'll see all year. All that should be motivation enough.
"Last year it was these two matches which really kicked us on and we went on a run of five or six wins and we want to do the same again."