We're headed down there the first part of October for a couple of weeks, most likely going to Bahia Concepcion and Mulege. 

After that trip I should be able to give you some first hand info. 

In addition, there is a few things which may of some passing assistance for you: 

1. On this web site find "Predicting Northers", by John Kinney which contains some pretty good info. 

2. A past post noted the following: 

The BEST place for gathering weather information these days is on the Internet. 

You CAN get access to the Internet in several places in San Carlos. 

There is access in Barracuda Bob's Coffee shop next to the marina office. The Marina Cantina has wi-fi access if you have your own laptop. Evie's coffee shop, across the street from the MarinaTerra Hotel at the marina has access. and the BEST broadband access I found last year (March 2004) was upstairs above Gary's Dive Shop on the main drag in the middle of town. 

I'm sure there are a few others. 

There are at least two Internet cafes in Mulege, a few in Santa Rosalia and several in Loreto if you get down that far. 

The SECOND BEST place for gathering weather information as it relates to sailing on the Sea of Cortez is from the short-wave SSB cruiser nets and VHF nets. 

There will be actual weather observations from various locations and cruisers around the Sea of Cortez in addition to an excellent forecast from someone who has accessed a LOT of weather information on the Internet and put together a forecast for the day and usually a couple more days into the future. 

Few of us have have a high powered SSB transceiver on board but a couple of us have a Grundig Yachtboy reciever which will pick up the short-wave nets pretty good. 

I'll list the frequencies and times below. These operate daily: Ham Nets In The Sea of Cortez 1) Picante net 6516 mhz, at 6:15 MST 2) Amigo net 8122 mhz, 7:00 MST 3) Sonrisa net 3968 mhz, 7:30 MST 4) Chubasco net 7294 mhz, 8:30/9 & 19:00 MST 5) Baja net 7238 mhz, 8:45 or 9:00 MST 6) Mañana net 14340 mhz, 10:00 MST 

3. In additon, you may wish to note, though not a completely accurate predictor, last years weather, around the dates you'll be there may be of some help. You can access that info by going to the Sea of Cortez web page, then to destinations, then to San Carlos and on that page note the "current weather" box. At the bottom of that box is weather forcast or something like that, hit that button and go about two thirds down to the box that allows you to cite the dates you're intersted in. Insert those dates and the info will pop up. 

4. Average Air Temperatures (Range) January - 60-75º May - 70-85º September-80-94º February-60-75º June - 78-90º October - 74-88º March - 60-77º July - 80-94º November- 69-80º April - 64-83º August- 80-94º December-60-77º 

Average Water Temperatures (Surface) January - 63º May - 77º September - 87º February - 64º June - 85º October - 87º March - 67º July - 89º November - 71º April - 72º August - 89º December - 65 

Hope this helps a bit. 

Tom