On May 8, 1846, United States and Mexican troops clashed on the prairie of Palo Alto in the first battle of a two-year-long war that changed the map of North America. The site preserves this notable battle and offers an understanding of the causes, events, and consequences of the U.S.-Mexican War. Summers are hot and humid, tropical weather systems generally affect the area from August to October, and winters are usually mild although cold fronts can drop temperatures by up to 30 degrees in about an hour.