Where are the best places to go in Mexico during the summer?

Im headed to Mexico in July and August (no choice in the timing - Im a teacher) and I want to sit on a mostly uncrowded beach and hang out with a beer, maybe do some surfing. Ive heard the west coast can be rainy and hot, and that many things are closed.
So where are the best sleepy beach towns to hang out and watch the ocean?

I was in Cabo San Lucas during winter, and it's quite relaxing!
If you want to do the surfing, you may go to Puerto Vallarta.
If you change you mind, and want to do a little party to.. You should go to Canc煤n or Acapulco. But Canc煤n in that time, gets a lot of rain :S

Good trip, and have some good Tequila! XD

Too many smokers in Mexico. You;ll have your work cut out for you. Report It

I think that Cabo San Lucas is great.

because of the climate, I never head to the beaches at this time of year. It's rainy and hot and that equals high humidity and mucho mosquitos. I prefer the mountains at this time (still there's rain)
talking with some Texans while in the Cancun area, they said they love to visit there in the summer because the crowds have thinned out, and rates are low. it's always beautiful.
my guess would be that the further north, the better (dryer) the coastal areas will be, but the Caribbean is unbeatable.

Playa del Carmen and all little towns along the Riviera Maya in the state of Quintana Roo.
I lived there the best 4 years of my life.

Then go to the sates, which do not have money for promotion, they have wonderful beaches (some of them with an exceptional prehispanic and colonial heritage):

Sonora:
http://www.gotosonora.com/

Sinaloa:
http://www.visitingmexico.com.mx/sinaloa...

Nayarit:
http://www.turnay.gob.mx/es-index.htm

Michoacan:
http://www.turismomichoacan.gob.mx/

Oaxaca:
http://www.oaxacamexico.com.mx/

Chiapas:
http://www.turismochiapas.gob.mx/lang.ph...

I would recommend the East Cape.
It's between Cabo San Lucas and La Paz however, they don't offer surfing.
www.casstours.com

No doubt about it Ixtapa-Zihuatanejo, its your place, one of the best beaches in Mexico, not crowded, in the pacific, nice place for surf, and a guranteed weather all year long.