How do I get rid of large ants in my apartment and why are they here in the wintertime?

Probably carpenter ant nesting in the wall or a hollow core door...too cold to go outside they tend to migrate inside. They will be more active between midnight and 4 am. The more you see in an area will determine where the nest may be...also look for a loose saw dust looking material that they kick out of the nest and it will pile up...look straight up from that pile and you will find a nest opening. You should be able to locate a specialized ant bait for them (they aren't attracted to the normal commercial ant baits) called Maxforce Carpenter Ant Gel, though hiring a pro will probably be a quicker remedy for them

There are some very good Ant Gel poisons at the hardware store. I forgot the name but you just clip the top off and put them around the apt. where you see ants walk the most. I used 4 (6 in a box) and within a week the ants were gone. I had a massive infestation of medium sized black ants. They were everywhere until I used the gel bait trap. Actually, they eat and walk in it, then return to the hive and spread it around. Eventually it kills the queen. Try it, it works!

Suprisingly, I had the same problem in our house last year.... I used ground cinnamon... It's eco/enviro friendly, cheap, and it really works!!

I took cinnamon, mixed with vinegar and lined my door ways, windows and any cracks where I saw the little buggers and viola, they were gone... We had what looked like queen ants (but a lot of them) they were huge... I was worried my son would be bitten by them... We have kids, and pets so the natural remedy was great!

Also, here are a couple of links with natural remedies for ant repellents:

http://www.stretcher.com/stories/980528a.cfm

http://www.gomestic.com/Gardening/Six-Natural-Ant-...

Give it a go and let me know what happens ;~)

Carpenter ants. Watch out for the plumbing ants and the painter beetles; and the roofer weevils.