Exterior Painting in Winter?

Is it too cold to start an exterior paint job?

They're planning to use SW Lattitude which does allow down to 35°F application but does the temp rating on the paint can apply to the first day only, or for several days of curing time?

Background: Having a new house built, outside is LP Smartside which is factory primed except on cuts. Forecast now says lows will be in the low 30s or colder for rest of the year, (then the rest of winter won't be any warmer!) If latex takes a month to fully cure (per reddit, not the paint can) am I going to have more problems from a) letting them paint on a day that meets the spec, or b) telling them to wait on exterior paint until spring?