Scottsdale Weather, When to Go and Climate Information. (Scottsdale, Arizona - AZ, USA) The city of Scottsdale provides a year-round mild climate, with over 300 days of sunny weather combined with low humidity, making Scottsdale a popular holiday destination. The summer months in Scottsdale feature a particularly dry climate, with temperatures at their warmest between the months of June, July and August, rising to around 40°C / 105°F during July.