Hi! My boyfriend and I are looking to visit Spain during the second week of August for about 5 days. Neither of us have ever been to the country and want to explore but not be overrun by other tourists (we were advised to choose Valencia over Barcelona). We're thinking we'd want to spend about half the time in Valencia and half the time in a beach town somewhere. Would love recommendations about where to stay (towns, airbnb, looking for more local experience), eat, and visit! We aren't wedded to any location yet.

Hi. I visited Valencia in Winter. I like this city very much but I remember the most Albufera near Valecnia and famous rice fileds. If you like nature and beautiful landscapes you must see it

Kris

The weather will be very hot there in August. Another month would be better for this area.

As Kathie notes, August will be HOT. You can get typical climate data from wunderground.com or timeanddate.com

If you do decide to go, you might consider Tossa de Mar for your beach time on the Costa Brava. And you might find some useful information in this trip report.
Four Awesome Weeks in the North of Spain and Catalunya

Valencia is a beach town..