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 in advance. March can be chilly, with daily temperatures in the 40s and 50s. The average high in June is 18°C (65°F), which is about as hot as it gets. May and June are the sunniest months. May and September the driest months. The farther west you go, the more likely you'll get rain. From November to March daylight hours are short, the weather is damp, and many places close.