Dismal, dreary, cheerless, dispiriting, bleak, desolate are comparable when they mean devoid of all that makes for cheer or comfort.
Dismal and dreary are often interchangeable.
Dismal may indicate extreme gloominess or somberness utterly depressing and dejecting.
Dreary may differ in indicating what discourages or enervates through sustained gloom, dullness, tiresomeness, or futility, and wants any cheering or enlivening characteristic.
Cheerless stresses absence of anything cheering and is less explicit than but as forceful as the others in suggesting a pervasive disheartening joylessness or hopelessness.
Dispiriting refers to anything that disheartens or takes away morale or resolution of spirit.
Bleak is likely to suggest chill, dull, barren characteristics that dishearten and militate against any notions of cheer, shelter, warmth, comfort, brightness, or ease.
Desolate applies to what disheartens by being utterly barren, lifeless, uninhabitable or abandoned, and remote from anything cheering, comforting, or pleasant.