My new Civic's owners manual says it should be 32 or 33 psi front and rear.
Myself I like having the pressure a little lower in the rear when unloaded.

I think I've heard about people using 36 psi in there tires and that must be "out of spec," however it might work well anyways.

I've been considering running slightly higher pressure for the winter,
for slightly better ground clearance mostly, but perhaps better bite in snow.

 

My Civic's recommended pressure is 30. (cold, front and rear) I would stick with what your car (or owner's manual) recommends.

Over-inflating your tires actually reduces your footprint, which could cause safety issues. Especially while driving in winter conditions. It also causes uneven tread wear. (center of vs. width of tread.) I would not recommend doing this.

Under-inflated tires, in theory, will increase your footprint. However, it also causes uneven tread wear. (outer edges of vs. width of tread)

A good set of all-season tires should suffice. (assuming you don't already have a set)


Edit: There's always studded tires or tire cables if conditions are really bad.

 

I like to go slightly lower in the rear because with much less weight,
you have a much reduced contact patch.
I do not drop the psi enough to make the rears compressed as much as the front tires,
but for most vehicles, I like to low enough psi it's about halfway.

My theory is, just looking at the front and rear tires,
you can tell that the footprint would be totally different when the car's unloaded
with the same pressure on all four tires.

*If I suspect I'll be loading up the car I like to put the rear pressure back up.

So far I've been using 32 psi front, 28 psi rear.
Civic 16" rims they recommend 32 psi.

 

I use somewhat higher pressure to help with gas mileage. If I see the middle tread wearing out ill lower it some. Right now 32-35 psi.

 

Studless winter tires (e.g. Bridgestone Blizzak WS-60, Michelin X-Ice Xi2) give better grip in most winter conditions than all-season tires, studded tires, or tires with cables/chains.

Huh? The size of the contact patches of the tires increase with less weight on the car (and also with lower inflation pressure).

As a general rule, the tire pressures recommended by the car's manufacturer (usually in the owner's manual and on the door jamb) are a great place to start. These should be measured while the car is cold (has been sitting outside out of the sun for several hours). From there, you can adjust up or down to your taste for handling, ride comfort, etc. Personally, I've found that the recommended pressures are usually pretty darn good without a need for changes, aside from racetrack usage.