Putting 0w20 in my engine while there's still a little bit of 5w20 in it?

I accidentally bought 0w20 last night not paying close enough attention in the store but I've also read that it's completely fine to put that in my 2003 Honda Accord bevause the 2 are interchangeable, some even say that it's better.
Would it be fine topping off with the 0w20 while I still have some 5w20 in my engine still?

Yep - it is just a bit thinner at very low temperatures. 0W20 is gradually taking over.

Should not be a problem since the two are interchangeable for the engine.

I have added 5w30 to 10w30 oil when I was required to add a half a quart.

The oils to not destroy each other.

God Bless

They are NOT interchangeable. Honda does not list 0W-20 in their spec list. This engine has variable valve timing and that mechanism runs on oil pressure. Read this post on why you should never use a different oil on a vehicle with VVT.

http://ricksfreeautorepairadvice.com/motor-oil-viscosity-warning/

Oil is Oil so they mix NO PROBLEM. Put them in a clean glass side by side and you see no difference because there's no difference except the 0W is a bit thinner than 5W at -40F which is in Antarctica. Otherwise you need sophisticated measuring equipment to see the difference. Hell you can't tell the difference between 5w20 and 10w30 without the same equipment. TRUE TOO.

You think it will be a problem? Why? There's maybe a pint of 5w20 left in the engine? No problem at all.