If people are dying near the equator from burning to a crisp, you have to wear clothing from head to foot. Even the Levant would burn you.
In turn you would move to the cloudiest, cave-iest places you could find, which all things being equal (and acknowledging a vastly-weakened magnetic field would demonstrably affect weather, although of course the argumentum on that very thing from this very event is stultifyingly nauseating) would be 500 miles either side of a line from Glasgow to St. Petersburg or maybe all the way around the Northern Hemisphere between Latitude 50 and 60, as Beringia's land bridge between Asia and the Americas was still open for business.
Where you would encounter your competitors the Neanderthals and as you have posted articles to this effect, been eliminated by humans in a very short timeframe, less than a millennium.
Just living in equatorial Africa would have let to, at least, big brimmed hats, irrespective of magnetic field shifts.