By the time December 1st hits, most cultural and weather standards consider the season to have shifted into winter. Meteorological vs. Astronomical Fall

In the (e.g., the US, Canada, Europe), the fall months are:

If you are in Australia, New Zealand, South Africa, or South America, the seasons are flipped. In the Southern Hemisphere, the "fall months" are

So the answer depends on your location. If you meant a general or US-based answer, are considered the fall (autumn) months.

In the Southern Hemisphere (such as in Australia and New Zealand), the seasons are reversed. Fall takes place during .