I want to know is it required for me(seller) to get a smog check in California if the buyer is from out of state(Washington), and he will be registering it in Washington?

 

no. if the car will be driven home by the buyer, he needs to make sure it's still registered. if it'll be shipped out, he will register it out of california. either way, sellers has no liability for smog check since it's going out of state.

 

Correct.

I prolly wouldn't hassle with a temp tag in CA if I was the buyer- just complete a transfer of sale, make a copy, tape it to the windows and head back to WA.

I am not worried about a 'registration issue' on the way home, but the seller should definitely make sure he is INSURED on the way back.

A