Dear Mike,
I do think such things impact us. For me, it's not so much the solstices, but the equinoxes. I find I have major events happen around those times, even if it's just a major change in myself. As for coincidences, I don't experience them.
Coincidence happening in groups has always been an interesting phenomonon to me. Generally, I take it as a sign that I am on the right path, but that's just my theory.
As always, thank you for this great site.
Best wishes,
Roxy