After spending about 10 days up in the North part of Vietnam, we flew south to Da Nang in central Vietnam.  In the north we were wearing our biggest jackets and many layers, it was probably 55-60 degrees, but we'd gotten so acclimated to 80-90 that we couldn't stay warm.  Just an hour and a half flight south meant back to tropical temperatures and loads of humidity.  We had heard only good things about Hoi An from all the tourists we met, and were really excited to spend the lunar new year there.