I always went with Mother’s Day as a target here. That’s the latest we’ve had a freeze in a very long time. Mountains of SoCal here. Your real risk is the lighting transition. If you’re giving them 18 hours of light inside, when you throw them outside, they will start to flower, then as the days get longer they will go back to veg. Basically you’ll confuse the shit out of the plant and your yield will suffer. Research the daylight length for your garden, then begin to match their schedules slowly before you put them out.