To put on a bonnet or hat of one in mourning is a sign that you will wear one before the year is out.
Peabody and Boston, Mass., and Niagara Falls, Ont.

To put on a bonnet or hat of one in mourning is a sign that you will wear one before the year is out.
Source: Current Superstitions (1896), entry 1208.
Fanny D. Bergen, editor.
Modern normalized navigation; the historical attribution above remains unchanged.