Solar Flux affects propagation by charging the ionosphere allowing HF propagation to 'bend' with the curvature of the Earth. That's the upside. The downside is that closer to solar maximum solar flares become more numerous and greater in class namely X-Class. Those cause temporary radio blackouts.
Best way to figure it out is turn on the radio and tune the bands. What may be good in one part of North America (or anywhere in the world, for that matter) may not be good in your section.