The best times to visit the Southwest are mid-March to June, and September and October. In July and August it's the peak holiday period, meaning roads are more crowded, prices are higher, and the best places are booked up far in advance. March can be chilly, with daily temperatures averaging 40 and 50 degrees Fahrenheit. The average high in June is 65 degrees, which is about as hot as it gets. May and June are the sunniest months. May and September the driest months. The further west you go, the more likely you'll get rain, but passing showers are much more common than daylong downpours. From November to March daylight hours are short, the weather damp, and many places close -- attractions as well as restaurants and hotels.