“Wearing horns and intimidating paraphenalia to awe your enemy is an old ploy.”
The Vikings traveling through Russia and down to the Black Sea were traders. Presumably they might have had a brief period of war and conquest before trading sites were established. The warriors might have dressed one way, the traders who had to negotiate with the local gentry would have wanted to look impressive to wow them. I’ll be that the Vikings who headed to Greenland the North America dressed quite differently. I’ll also bet that the common people doing farming and rowing also dressed much more simply. The guys doing the trade negotions were not doing the rowing, and the guys/gals doing the farming, fishing, and rowing did not get preserved in fancy burials.
Regarding temperatures and scant clothing. The Scandinavians are notorious for taking it all/or mostly off in the warm weather. They have needed the sun exposure to make Vitamin D in their skins and strong bones thereby. Furthermore, people living primatively are often more hardy. Magellan (I think) reported on women of Tierra Del Fuego nursing babies at bare breasts while sleet was falling on them (the breasts). Salacious factoid alert [stop here if you would be offended]. The Fuegan women could require that the men wear a braided hair colar around their penis for sex. Presumably, their bodies were so shut down from the cold they needed the extra stimulation (like the barbs a male cat has, ever wonder why the female cat yowls so?). They could get a divorce if their mate refused, the women, not the cats.
“...they needed the extra stimulation...”
Nah. They just liked it.
That was Alexander von Humboldt who made that report.
He reported that these nearly naked people were short and plump and made their living from the sea while there was another group who were tall, slim (who wore animal skins)and who made their living as hunters on land.
Because the shoreline was so rocky and the water so rough, the boats were anchored off-shore in the kelp beds. It was the woman's chore to swin out to the kelp beds and fetch the boats for the male fishermen.
A diet high in seafood (high vitamin D content) would/could eliminate that problem.