when does the fishing normally get better here in southern CA lakes such as Cachuma, lopez and Santa margarita

South of you (Orange County), it has been wide open for the past 4 weeks.  We had multiple days of warm temps at the end of January & in mid February that kicked the water temperature into the 60's and it has been like that all month.  I am looking forward to the full moon this Thursday, I am betting that with the weather pattern (3 days of warmer weather after a few rainy days) and the lunar cycle will push the biggest females into shallow searching mode.

 

That said, I would guess that with the distance you are north of me, your March or early April will be like our February.  I'm sure that WRB will have more specific info for you.

The pre spawn bite is going on at those lakes mentioned. Pre spawn doesn't mean the bass are active everywhere in the lake, just the opposite the bite is usually very isolated areas and depths.

Tournaments held during this time period almost always have mixed results, a few anglers catch heavy limits and most in the tournament struggle.

Your sonar unit is your eyes under water where the bass are located, deeper than you think.

Start by metering major points down to 50' or more to determine where the bait is located and where the majority of the bass are located. Get out the lakes map and look for off shore areas with structure similar to the points where you metered bass. Now spend time learning when those bass feed and what lures work and don't work.

The bite gets good fast when you know what is going on at the lakes you fish.

Tom

My home lake runs pretty much East to West with a majority of the coves on the north or south side of the lake.  On Thursday, in some of the north coves, fry have already hatched & are hanging around docks (I assume the male, if he is still there, is under the same dock).  In other coves, including those at the East or West end of the lake, I saw some males on beds, pretty shallow.  On the coves on the south side, most of the fish are still on the outer points.

 

Pretty textbook, except for our dock.  It is on the south side of the main lake & a male built a nest about 3 weeks ago off a side that doesn't get much shade.  Yesterday, there was a ball of a thousand plus fry moving in & out of the shadows.  Apparently the bass that built that nest refuses to be part of a pattern.