I was looking for them the whole evening yesterday.

[englishhobby]

Is the sentence correct? natural?

I always lose my glasses: I was looking for them the whole evening yesterday.

 

[Raymott]

Yes, with a semicolon instead of a colon.

 

[emsr2d2]

In BrE, you could also say "I was looking for them all yesterday evening".

 

[englishhobby]

Can we say "I was looking for them for two hours yesterday" in the same context?

 

[emsr2d2]

If it's not important that it was evening, then yes. Your suggestion doesn't specify a time of day, just that it was for a duration of two hours yesterday.