I'm generally not here in proper summer, but shady sectors in Siurana and Margalef provide some respite from the heat and then of course there are loads of places further up towards the Pyrenees.
La Riba is fine without a mat. The landings are flat in general and loads of traverse problems.
The boulders are here: 41.317518,1.166908
And the parking here: 41.320157,1.175245
Guide available from the refuge up towards the sport crags. Don't go expecting Fontainebleau but it's pretty decent and a nice spot once you're out of the grim town itself.