Frank J. Wilstach, comp. A Dictionary of Similes. 1916.

Unkind

Unkind as fate.
—Anonymous

Unkind as hail.
—Ambrose Philips

Blow, blow, thou winter wind,
Thou art not so unkind
As man’s ingratitude.
—William Shakespeare

As winter’s frost unkind.
—Tobias Smollett