We just visited in November and really enjoyed that time of year. It is low season so you won't find so many tourists, which can result in a very real experience. The weather was definitely variable - some days it was hot enough for a t-shirt and jeans, other days I needed a heavy trenchcoat and it rained.
Q. What effect does the barometric pressure have on humans? Can it cause headaches and other discomforts? A. Differences in air pressure because of the weather or changes in altitude can have noticeable effects on the human body, though some people are more sensitive than others.
Try using our barometric pressure calculator to see how air pressure changes at high altitudes. Or use the altitude oxygen graph to see how much less oxygen is available at any altitude. The pictures above demonstrate the effect of altitude on barometric pressure. I sealed a plastic bottle like this one in La Paz, Bolivia, at an altitude of 3600m (about 12000ft).