Weather Wise, San Diego
First, let me say that San Diego does in fact have four seasons (granted that it's sunny 95% of the year), so having said that let me provide you with a rough guide as to what to wear while visiting. In the winter, it is highly advisable that you bring an umbrella (it does rain), sweats (as it does get cold) and a warm coat (in addition to your shorts).
When winter gives way to spring, keep the umbrella handy but you can now wear a light jacket and pants to keep you legs warm (again shorts and t-shirts are good during the day). Summer can be quite nice (great ocean breezes in the afternoon), but then again if you travel inland it can be quite hot!!!
Sunscreen is a must, but most likely you'll be running around in loose fitting clothes. And now on to fall/autumn...as it brings cooler tempratures which calls for lightweight clothes during the day and something warmer for the evening. I hope that this helps :-)
Toiletries and Medical Supplies: Bring the usual things that you travel with...if you forget anyting there are enough discount stores here (Wal-Mart, K-Mart, Target, etc.) for you to purchase them.
Miscellaneous: Ahhh, the weather here is perfect, well anyway it seems to be everytime I come here, year-round.
Vacationing in San Diego is like visiting a 70-mi/113-km stretch of seaside resort. You've got your sun, your surf, your sand. You can lounge on the beach, surf in the sea, snorkel in the cove. Take a cruise for an hour or an evening, dine at water's edge, explore waterside caves. In fact, it's very difficult not to be in, on, by or under water in this most oceangoing of California cities.
If you prefer to golf inland, choose from 82 courses, most of them public. Hiking, cycling or horseback riding? Easily done. So are a host of other pursuits. San Diego's a versatile playground.