Greatly depends on the weather forecast. In cold months, around here at least, subsoils directly beneath the topsoil are 2% to 6% above optimum moisture conditions. If one hopes to dry subsoils to allow for fill placement, best to strip topsoil as soon as a dry 'window' is forecast. A trick many graders do around here is to strip topsoil at the end of the day if nightly forecast calls for low humidity conditions. Even if below freezing at night, 'jack-frost' tends to form on the wet subsoils (water rises to the surface of the subsoil and freezes when it hits the cold air - kind of pretty when it gets 2" to 3" in length). The first thing a good grader does in the AM is lightly scrape the surface to remove the very wet material (can do when ground is still frozen), scarify the underlying material, and begin fill operations.
The most important thing to remember is the soil type - who cares when soil is sandy. When clayey or silty material at near-surface, it really matters