There will be a lot of snow and it will be some kind of cold (-5 to -15 celcius generally), get well equipped for this type of weather especially if you wanna go around the city, which is enchanting at this time of year.
The Old Town is the most beautiful part of the city, especially during winter. You can go down on the shore, there's a lot of nice dinner place. If you go up north a little bit, you will be able to walk on Ste-Catherine and do some niiice shopping.
On this same street (Ste-Catherine) walk (or take the metro) towards the east to Station Beaudry and you will be at the entrance of the gay village.
Apollon, Unity and Sky are the main 3 gay clubs. They're a walkable distance from eachother, so no worries !
Have fun !