Lately there has been some discussion that barometric pressure plays a big part in the BP breeding cycle.

In their natural habitat, equatorial africa, there is very little difference in light cycle or temperatures between summer and winter. However, winter is the rainy season, and along with the rain comes a lower average barometric pressure than during the summer. In fact, it's the lower barometric pressure that draws the rains to the region in winter, and the higher pressure pushes them away in the summer.

So, that's my theory.

It's supported somewhat that people in the northern part of the country, where the weather is already shifting significantly, are already getting successful locks. While people in the southern part of the country, at least from the reports I've seen, are having a harder go of it, and their weather is still pretty nice.