The Sea of Cortez is one of the most popular cruising spots on the west side of Mexico. Every year, there are more and more boats that make the trip south in the fall. After reaching Cabo San Lucas, some boats go farther south but most will go around the tip of Baja California and North to La Paz. In the winter, the southern part of the Sea of Cortez can be windy but it is still nice. The northern part of the Sea of Cortez can be very windy in winter. The wind can blow 20 to 30 knots for two weeks at a time. During the winter that we were in the middle Sea of Cortez, the wind would blow 20 to 30 knots for two weeks then there would be one 5-knot day and then 20 plus again for two weeks and so on all winter. At night, the wind would be strong enough to pick up the dingy and throw it against the side of the boat. The middle to upper Sea is best to see from April to the first of November. The exception to this is Bahia Concepcion. It is 10 degrees hotter there than anywhere else including the anchorage at the entrance to the bay. It is best to go there when it is cool.
The best fishing is in the summer but there are fish to catch in the winter. You can catch dorado, yellow fin tuna, and even marlin. There are a lot of skipjack out there too, so be prepared for lots of different kinds of fish. (hint: soak skipjack in vinegar and soy sauce; it will taste good)
We have spent three winters and part of a summer on the west coast of Mexico. In that time, we have found some places that we really like. Two of those places are Isla San Francisco and San Juanico.
Isla San Francisco is a small desert island about 40 miles outside of La Paz. No one lives on the island and there is no fresh water. The anchorage can be rough at times but it is a nice place.
San Juanico is north of Loreto. It has seven beaches and you can spend a lot of time in this place.
Another place of interest is Honeymoon Cove on Isla Danzante. We found a rock there and I have a picture showing where the rock is.
I have compiled a list of marinas in the Sea of Cortez.