It's San Diego: we have a consistently perfect climate
We are so lucky  

There are quite a few of micro climates in Sd.  Just an example.  Torrey pines can be socked in w marine layer then you drive a half mile inland to utc and it's sunny and warm.  Del mar same way way...when the SD fair starts people think it's all sunny and nice and ultimately it's overcast and cool.  Check weather channel before your trip for accurate 10day forecast and you should be fine.  Enjoy your stay.  SD is a great city with much to offer.

America's Finest City!

Year round we have the best weather.

February and March get what little rain we have.  May and June often have overcast until late afternoon.  But for some reason we can get false summer in April.  Temps into the high 80s.  But the ocean water tends to still be colder than most people like.

Of course we can still get late rain or early "June gloom" in April.  You are beating the tourist crowd unless some people are here for their spring break.  I recommend April as a good month.

Once we planned a trip to Big Bear in April, hoping to do some jet skiing on the lake.  Instead it unexpectedly snowed and we did that kind of skiing instead.  That was the only time I ever had to use chains in southern California.

Fun in the Sun!

Scorching Hot!!! Definitely so nice down by the beach!