Not sure where you'll be flying FROM, but Canada, Toronto specifically has price fluctuations depending on season. Christmas/New Years expect to pay a premium, March break as well.
Airfares can and often will be a bit of roulette - do I lock in now, guarantee my dates or wait and see IF it drops...and maybe not have seats for everyone in my group.
Some sites offer price drop guarantees, Flight Network for example that lets you take a lower price and bank the difference for future travel. They will NOT watch flights for you, so you're checking every few days.

In numerous trips to this part of the world, my $0.02 is, if you find your flights on days you want at a price you're comfortable with - pull the trigger. Someone gets a few dollars off the same flight - well nice for them, but I don't sweat it.