I think the regional component is stronger in the south and midwest. Women around Boston always went "bare-legged," as soon as the snow melted when I was a kid. Since I lived in AZ when I started working, I wore pantyhose AND a suit when it was often 110 degrees outside at the beginning and end of the school year. I still wore them at times my last few years of teaching and about 4 years ago, I bit the bullet and actually went without pantyhose to high holiday services. Surely, G-d was about to come down into the sanctuary and give me a lecture. But now, I work with almost all younger people, who rarely get out of jeans.
Heck, I wore white gloves to Bar Mitzvah parties when I was in middle school. And shoes dyed to match my dress.
Then 1968 hit and that was it.