Thats coastal California up and down the state. We might look tropical-but we aint. Its just for those few weeks a year does the weather match the look of the tropicals-that do well with less than tropical heat. Your young plants show how some plants are more delicate at small size..and have no defense against molluscs. Boost with fertilizer,as warm a spot as you can find for seedlings in started in pots,and dont put them in ground too soon,so soon in the spring.

You're experiencing the burst in the bubble of new California transplants who come here thinking the whole state is warm all year. :-) This cool spring weather is typical for this time of year. I am often cautious about starting new plants outdoors, or early-Spring pruning, to protect seedlings and tender plants.

Most plants care much more about the temperature of the soil that their roots are in than they do about the air temperature where their stems and foliage are. The problem with spring on the West Coast is that soil temperatures typically lag way behind air temperatures because in Mediterranean climates, soils are still wet in spring (compare this to Arizona, for example, where soil temperatures rise precipitously through March and April). In a La Niña year, this effect goes even deeper into late spring. It may feel like its getting summery to you, but soil temperatures are still cool as far as a plant's roots are concerned. Once the soil dries out a bit more it will warm up faster and plants will start making vigorous growth.

dick_sonia: Thank you for the better scientific explanation.

stanofh, jenn, and dick_sonia, thank you all for the explanation of what is going on here in coastal California. It sounds like a I jumped the gun. And I probably should have waited and not water heavily on the hot sunny days like I did. Because sure enough, the day after I watered it would return to being cool and overcast and now I have plants sitting in moist soil with sub optimum weather.
I will be cautious from here on out. Thanks again!

Yes that's the thing: the soil temperature is what counts, not the air. That's why we can plant green beans in September and get a big crop for thanksgiving--the soil is still warm even if the nights in autumn get a bit chilly.

I start zinnias in June, beans and cucumbers in May.

Socalgal, Thanks! That makes sense. I already started zinnias and beans so far the earwigs haven't decimated the seedlings; we'll see. My first cucumber seeds rotted (too early I know), so I'm going to start them again soon in May like you mentioned.