Sunscreen absorption time?

Sunscreen is a must in this weather.

When I go out for a quick trip, I just apply sunscreen and head out right away.

Is it effective to block UV rays even if I go out immediately after applying sunscreen?

Or I'm not sure if it's more effective to apply it beforehand and let it absorb before going out.

What I heard somewhere is that going out It is recommended to apply it 30 minutes beforehand. I heard

When I'm actually getting ready, I find myself applying it right before going out.

I'm really conflicted.

How do you guys do it?