I don't believe it has to with solar flares, at least not directly. It has to do with the fact that the satellites are "parked" in orbit directly over the equator. Imagine taking the entire "ring" of the equator and expanding it outward a few thousand miles. That's where the satellites are. In the spring and fall, when the sun crosses the equator, it happens that, for a few minutes during the daytime, and for a few consecutive days, the sun gets in a direct line with your dish and the satellite. When that happens, you may (or may not) experience signal loss. The dates, times, and duration of this phenomenon is dependent on the lat/long of your dish and the location of the satellite to which your are aimed. That's why the calculator that DJdish provided asks you to enter that data for it to calculate the schedule of possibe outages.
I have never personally exprerienced this phenomenon, even though during one outage season, I tuned in every day to see if it would happen.
But check the calculator....if the dates have passed for you, your problem lies elsewhere. Perhaps your dish pointing needs to be fine-tuned???