Can one use an ordinary plastic bag over ones hat on shabbos on a rainy day? Can one wear gloves on shaboos?
An ordinary plastic bag cannot be used in a place where there is no eruv. The plastic bag protects the hat and not the body, and it is not a malbush (an item of clothing), and therefore it cannot be carried on Shabbos.
The Shulchan Aruch (301:37) cites a dispute concerning wearing gloves in an area where there is no eruv, and writes that one should be stringent for the prohibiting opinion. However, the Mishnah Berurah writes that one can be lenient, in consideration of the fact that we barely have a full public domain in our days.
Therefore, it is generally permitted to wear gloves, and the custom is to be lenient in this matter.