We live in North Central Texas, a part of the
Cross Timbers Region of the central USA. The region represents a boundary between the forests of eastern North America and the southern Great Plains.
Weather here is variable from year to year. Because of topography and established weather patterns, it is very dry to the West and very wet to the East of us, but that wet/dry line moves East or West as those established weather patterns vacillate. Some years here are dry, (producing a dearth), and some years are wet, (potentially producing a bumper crop of honey if the timing of rain is good).
So my answer to Ef's question is we have a dearth sometimes and sometimes not. When it occurs, it is usually mid summer (July/August). We hope for a good fall honey flow and it appears if weather (rain) permits. The problem is that here in Texas we can go six months without a drop of rain and get 4 or 9 inches of rain overnight. We average 32 inches of rain each year, but it may fall on six days of the year leaving a lot of dry weather in between the rains. When I get it figured out, I'll let you know.
P.S. We feed when necessary, but usually let the bees have their honey through the dearth.