Nothing beats some great ice cream when the desert gets hot in the summer. My favorite spots in Tucson to try are:
Hub Restaurant & Ice Creamery: At 266 E Congress, this is a popular restaurant and ice creamery. They recently opened a store across the street, Hub Ice Cream Factory, at 245 E. Congress just for their great ice cream. I always have to go back when I am in town!

I also found Hub Ice Cream at Café con Leche located in the American Eat Co., a food hall located south of downtown at 1439 S 4th Ave.
Across the street at 250 E. Congress is The Screamery Handcrafted Ice Cream which has multiple locations in Tucson and Phoenix. The coffee toffee flavor was great for dessert after dinner nearby.

Cashew Cow: Located in Broadway Village at 16 S. Eastbourne Ave., next to Bario Bread, Cashew Cow turns cashew milk into tasty non-dairy ice cream.
