Too Late/Too Early?

I've gotten a bit off track on my gardening in the last two or 3 weeks while trying to prepare for a yard sale. I'm glad I kept track of what and how many of everything I've sowed on an extra calendar, but I've begun to forget the general plan I had in my head. Now the problem I'm looking at is if it's too late to try to start growing some of the seeds I wanted and too early for others. This is always on my mind being in the Southbay area and the weird weather we've been having the last year and a half.

My major worry is the last frost date. Normally we just don't have any frost at all. Normally. Once every few years there will be one (maybe two)  mornings where I head out the door to work and find the grass frosty and the birthbath icy. Once the birthbath water was frozen solid...that was kind of funny. Anyway, with the weather so abnormally cold for my area this year I've been trying to plan around figuring we're likely to have a night of frost in February or March. I don't want any of my green babies to get frozen to death after all. But will one night of Socal frost really kill them? 90% of any seed and new shoots will be in my back patio area which is fairly sheltered, I can't remember if previous nights of frost affected anything beyond the open front and side yard areas. Will they be ok back there? I don't think any of the plants in the front and side yard were damaged from frost before...but I wasn't paying attention at the time, they were all dad's plants then. Am I wasting my brain cells and planting time worrying about frost at all?

Besides the frost question I'm concerned I waited too long to start some of my seeds, especially the spring veggies and bloomers. In my area "Spring" is practically over by May and "Summer" lasts into October. That said, should I stop planting anymore spring veggies that might not come into harvest before the summer heat?! Is it too early for my summer veggies?!

Ok, time to just go experitment and remember to record what happens so I know better next year...