It starts out really, really bad, getting slightly better as the engine warms up. Its hard to say about the ambient temp, but that does seem to be a factor.
Most people I know here in LA don't run chokes and say they don't have problems, so I think I'm just running much too lean anyhow.
Usually when one has great difficulty getting warmed up it's because it needs plugs, has the wrong plugs, needs more initial timing, or is running too lean.