We order a mix meant to stand up to freezing and ice melt. Air-entrained concrete has tiny air bubbles worked through it, which helps a soaked slab survive freezing and thawing and keeps ice melt from scaling the top, so it doesn't flake off in thin chips. When you compare bids, ask each contractor what mix they're ordering.
We pick the pour date by how cold the nights get, not just the afternoons, because cold slows the set and can freeze fresh concrete before it gains any strength. If the timing looks tight, I'd rather tell you to wait for a better week than pour into bad conditions and have you pay for it later.
If the budget gets tight, the base is the last thing I'd cut. Nobody sees it on day one, so it's tempting, but a fancy surface on a poor base cracks just the same. Once the base is right, stamped concrete can give the top a pattern, and a concrete sidewalk can tie the patio to the driveway or the back door.