He explained me the situation clearly.

[shatilof]

Is the sentence He explained me the situation clearly correct or should we rather say He explained to me the situation clearly? Why?

 

[Piscean]

Yes, we should. Or: He explained the situation (clearly) to me (clearly).
That is the construction with should.

 

[Kjaadere]

It should be 'He explained the situation clearly to me'.

That's how 'explain' works. You can explain something to somebody. You can't explain somebody something.

 

[Tarheel]

"He explained the situation clearly" is most likely.

Does the reader (or listener) not know who the person is talking to?