 Along with its wine, Walla Walla is known for its sweet onions, which is a local food and wine pairing favorite, especially the Merlot grown within the appellation.The region is generally wetter than the rest of the Columbia Valley, receiving more than 20 inches (50 centimeter) of rain on average each year.The area between the town of Walla Walla east to the Blue Mountains is the wettest with each mile from the city eastward to the mountains seeing an addition inch of average rainfall.