When should I start growing my vegetable garden in Orangevale, CA?

[OingoBoingoGirl]

I live in Orangevale, CA and I'm planning to grow a vegetable garden. The vegetables I am including in my garden are pumpkins, summer squash, tomatoes, and carrots. Our cool weather and rain should be gone by mid-April. I need to know what is the best time to plant them all at the same time.