Are tubes really “warm”?

Of course if you’re going to play CDs with them it doesn’t really matter since CDs are lacking in warmth and air anyway. You can’t turn a pig’s ear into a silk purse. 🐷 

Not with Audio Research. They make tube gear that sounds like solid state. Never understood this brand. 🙄 Why use tubes in the first place if you aim for a solid state sound ??...

Good post @noromance 

The tube sound for me has always been about the presentation, not the linearity of its FR.  There is a holographic nature and weight to images that can be tough to get right with solid state. For me, if a tube amp sounds 'solid state', it means there is no real soundstage depth or weight to images - a flat sound if you will.  Some tube amps do sound like that, and the opposite is true for solid state amps sounding like tube amps, but it is much rarer to find the latter.

*are tubes warm?*, 
 depends on make of amp/design. in general , no , not muddy (=warm). 
but most ~~certainly~~ not sterile sounding,  that is not clinical as their nemesis, the *other* amp design,
(hint = ss amperage)
yeah i am  #1 basher. of ss design. 
The ss groupies just hate me so...

Summarizing the responses thus far:
Tube fans believe that, relative to ss, tube electronics have naturalness of timber, fullness and air.
Haven’t heard from those who favor ss. I’m guessing that they believe tube “warmth” is a lack of musical dynamics and punch - although I, myself, have not found that to be the case with tubes.
I think we should retire the term “warm” altogether, except to denote preponderance of bass relative to treble, which either tube or ss electronics may exhibit. The stereotypical “Tube sound is warm” seems incorrect.