You can mimic mother nature and sow either in the fall or winter, depending on your region.
In climates with cold or freezing winters, wait until November or early December to sow the seeds. You want to have several hard frosts and freezing nights, so that the soil cools sufficiently to well below 55 degrees, so that your seeds don't sprout prematurely. Or, wait until a big snow is predicted, and scatter the seed before the snow flies.
In warm winter climates that do not get a winter freeze, wait until the late fall/winter rains to sow the seeds. This will provide ideal germinating conditions. Winter sowing is especially helpful in desert climates, where the hot weather arrives very quickly in spring and creates hot, dry conditions that can kill tender seedlings.