Welcome to San Diego. You wont need your cold weather gear out here.
If you go down to Kearny Mesa, there is a place on Ruffin Road called American Shooting Center (
http://gotammo.com/). Nice place, but the owner is a little touchy. They also do (did?) small arms classes for the Marines out of Miramar. They also have a few interesting long guns and a wide variety of pistols for rent. Their range prices are on the high side.
There is a place in downtown San Diego on Kettner Blvd called Discount Gun Mart (I crap you negative on that name) that has an indoor range. Nice people, but they jerked me around on a couple of special purchases a little too long. Have never been on their range, and they also rent, but only pistols.
Iron Sights in Oceanside is the best indoor place in San Diego that I've been to. I am willing to drive from Poway to Oceanside to shoot there. Good people, good prices, and they aren't anal about you picking up your own brass. Weekdays are the best, of course, and they are open pretty late; 10:00PM I think. (Note: I do not work for them, nor am I getting money for this endorsement.)
I have never been down to the South Bay Rod and Gun Club, so cannot comment. Certainly, that's where a lot of the CASS people seem to hang out.
The range out in Ramona has been closed for lots of years, or so I've been told. Too many houses grew up nearby, and liability got too high.
There is a skeet only range near MAS Miramar. I've never been out there (I don't own a shotgun, yet) but have heard nice things about it. I dont know how many stations they have, but it seems to be enough to keep most people happy.
I used to go out to the Pala Campground, but they closed it for a few months a couple of years ago; I do not know if it ever re-opened (judging by the pervious messages, it has). I quit going out there and paying their $20 range fees when some friends introduced me to some nice places out in Ocotillio Wells (it's a wide spot on 8 out in Imperial County). There are some BLM areas that a shooter can easily get 100 yards (if not more) without danger of hitting anyone. (Plus, the weather is getting cool enough that you don't need to worry about getting 2nd degree burns from your black guns sitting out in the sun for five min.) The real downside is that loong drive (maybe 100 miles each way) from Fallbrook. Of course, if you car-camp and make a weekend trip out of it...
Hope this helps.