Be sure to sign up for the Southbound Yahoo Group -- southbound_group : The Southbound Group
You'll get lots of great info from people who are there now.
We cruised that area for 6 years and I gave the hurricane prep talks at the La Paz Bay Fest a couple of times. If you look at the historical hurricane tracks, month by month, it's pretty easy to see where you should be and when.
In the Sea of Cortez, the heart of the hurricane season is August 15 to October 15; in Banderas Bay, it starts sooner and ends later.
The typical summer pattern for boats in the Sea is to head out from La Paz at the end of April, make their way slowly up to Puerto Escondido/Loreto for several months. Get to Concepcion Bay for the 4th of July, spend a bit of time there, do the last big provisioning (and get cash -- last ATM stop) in Santa Rosalia and leave Santa Rosalia the first week of August. Head north to the BLA area, staying within a day of Puerto Don Juan (great hurricane hole, plus by the time storms reach that far north, they're usually trop storms, not hurricanes). Stay in the BLA area until mid-October (in Oct you may see whale sharks there!) (depends on weather patterns that particular year) when you'll start getting some northerly winds. Then start meandering south, getting to Loreto/Puerto Escondido by Halloween and on down to La Paz just ahead of the Ha-ha'ers.
Some of the marinas in La Paz are good hurricane holes, and Puerto Escondido and Puerto Don Juan also are. If you opt to stay in the Puerto Escondido area for the summer instead of heading further north, definitely dive on your mooring yourself -- some are well maintained, some haven't been checked in a while. PE is likely to be hit by a hurricane most years but it's a very good hurricane hole (we rode out Marty in 2003 there).
If you stay in Cabo or go up the outside, you'll have to watch the weather very carefully. Boats do it every year, it's not impossible, just watch it and have a plan.
In that whole area, it's rare that a trop storm or hurricane will hit you by surprise -- they form off Central America or the very southern part of Mexico. So while the exact path won't be known, the fact that there's "something" out there is known well in advance.
I have a bunch of info both about how we prepared for hurricanes, got weather info and more on my blog if you want more:
Hurrican Prep Info
Have fun -- the Sea is fantastic in the summer. Very clear waters for snorkeling, great fishing, etc. Yeah, it's hot -- but a few wind scoops and fans will help . . . as will going for a swim!