Where are we going?

(1)Let's go somewhere warm.


(3)Let's go anywhere warm.

Can I say (3)?

If I say (1), I mean I want to go out but I haven't had any idea where to go yet. If I say 'anywhere,' I mean it doesn't matter where we are going;anywhere will do. About number 3, I've got zero hit on the Google. Emotion: crying

I want to express the idea that anywhere will do but it has to be a warm place.


Both nos.1 and 3 sound natural to my ears.

(I got 736 google hits on go anywhere warm.)
If this is in response to the question at the top of your post, you should leave off the "Let's go..." part.

"Let's go somewhere warm." = Let's go out. I haven't yet decided on where we should go, but anywhere will be fine just as long as it's warm.

Anyway, "somewhere" is the word you want. My natural inclination would be to use "someplace" instead, but that's just me. "Anywhere" just sounds awkward.
Site Hint: Check out our list of pronunciation videos.
 davkett's reply was promoted to an answer.