August and September are our hottest months here. Carlsbad is close enough to the coast, that it is usually breezy.
August won't be as crazy as July, but there are a lot of last minute visitors to San Diego, as well as the local crowd. Monday would be far less crowded that Sunday. If you plan a beach day or something like that, do it Sunday. If you plan to hit SW, DL, LL...then LL is the best choice for Sunday!!
Have fun!!! Last year I was able to score some awesome coupons for LL, if I do again, I will post it on this board. I mailed out over 200 coupons last year!!! So, check back.
Amy