Is it proper to wear white pants in Italy after Labor Day?
There is no "Labor Day" in Italy.
May 1?
I wouldn't, partly because of fashion, but mostly because of dirt. It seems like the times I've been to Italy, the stores were dominated by a single color that changed with the season. Examples include white one winter and yellow one fall. Whatever it is the fall you go, it is likely to be reflective of the Pantone colors for the season. This is the link to the fall ones for this year: http://www.pantone.com/pages/fcr.aspx?pg=21058&ca=4. Gray and purple seem to be big in lots of locations. Those translate into "turbulance" and "acai" for Pantone this fall.
Wow!!! Thank you!!!!