2 feet or less could be glass calm, considering the "less" report. I have been anchored perching with the wind blowing from the east, flags on Kelly's Island blowing south, and flags dead calm when I get back to the dock. Open water measurements are always different that near shore ( five miles or less).

Buoys measure the height from a calm lake to the top of a wave. They do not measure the trough, hence double the number to get an idea of how much rock "n" roll is expected. For example, 2-4 foot waves will have a trough of about the same height so you will have a 4-8 foot distance from top of wave to bottom of trough.