As for the temp differences, I personally run hot so if it gets a little cold every so often, it doesn't typically bother me - I pack for what I'll be experiencing the most. But I always fly in pants so that helps with colder temps. I like to have at least a couple items from the "opposite" temps I'm expecting, just in case. Short sleeve tee I can wear a sweater over when it's cold, just in case it gets hot. The pants. Maybe tights, a fleece cap & gloves if I need to be outside in cold temps. I too have thinsulate LE coats that are great - but for me, I wouldn't bring unless I knew I'd be outside in cold temps for more than 30-45 minutes regularly. Again - I run hot, so adjust based on your norms. But lightweight warmth -in a packable coat, large scarf etc - definitely better than anything heavy wool....(I also never travel with denim - I don't wear it at home very often so I don't travel with it either - slim fit black pants work much better for my personal style, and are easier to dress up (esp for business meetings - I'm often combining work & leisure trips).