What is the average temperature diffrence in july between two cities

July is the hottest month of the year for most large US cities. Daytime temperatures above 80 degrees Fahrenheit (27 degrees Celsius) regularly occur nearly everywhere. The exceptions are cities along the Pacific coast. Seattle, San Francisco and San Diego stay cooler than elsewhere.

Phoenix and Las Vegas top the list this month of the hottest major cities in the United States with July temperatures averaging highs of well over 100 °F (38 °C) by day and nights that usually remain above 80 degrees F.