Quote Originally Posted by Hamish
Although our opinions of 'formal' and 'informal' differ on either side of the pond, I would certainly go with the others and recommend long sleeves.

The thought of attending a wedding sans jacket is almost more than my system can take, but I know that's the sort of thing you guys do over there!!

Comfort is important, but so also is the show of respect you have for your hosts and those around you. We cannot, nor should not, put our own comfort above all else, at least not under such circumstances.

Whatever; enjoy that wedding.
Ham, it's a bit different over here. I'm not sure what part of Pa Allentown is in, but here in Va, a temperature in the 90s F (32 to 35 C) would also be accompanied by humidity in the 75 to 90 percent range. This would lead to a comfort index over 100. Taking off a jacket in those circumstances can often be as much about avoiding heat stroke as about comfort. Some parts of Pa are similar in climate.