“Why don’t ghosts like rain?”/“It dampens their spirits.”

A popular Halloween riddle about ghosts is:
 
Q: Why don’t ghosts like rain?
A: It dampens their spirits.
 
The joke has been cited in print since at least 1987.
 
“Why do ghosts like to ride in elevators?”/“It lifts their spirits” is a similar ghost riddle.
 
   
Google Books
May 1987, Boys’ Life, “Think & Grin,” pg. 65, col. 2:
Nit: Why do ghosts get upset when it rains?
Wit: I dunno. Why?
Nit: It dampens their spirits.— Milton Doane, Shreveport, La.
 
23 November 1987, Indiana (PA) Gazette, “Mighty Funny’s Mini Jokes,” The Mini Page, pg. 4, col. 2:
Q. Why don’t ghosts go out in the rain?
A. It dampens their spirits.
 
23 July 1991, Morning Advocate (Baton Rouge, LA), “A Little Bit of Humor,” The Bubble Gum Rapper, pg. 1, col. 4:
Kristen: Why don’t ghosts like to go out in the rain?
Gail: Because it dampens their spirits.
   
Google Books
July 1992, Boys’ Life, “Think & Grin,” pg. 72, col. 1:
Pee Wee: Why don’t ghosts like rain?
Stilt: I can’t imagine. Why?
Pee Wee: Because it dampens their spirits! —Louisa Walwark, Oak Park, Ill.
 
Google Groups: alt.tasteless.jokes
Happy Halloween
Robert Nykvist
10/29/94
(...)
Why don’t ghosts go out in the rain?
It dampens their spirits.
 
Google Groups: bit.listserv.dsshe-l
Happy Halloween
David Sweeney
10/31/97
(...)
Q: Why don’t ghosts like the rain?
A: Because it dampens their spirits.
 
Twitter
Oly Grocery Outlet
‏@OlympiaGO
Bad Joke of the Day:  Why do ghosts hate the rain?  It dampens their spirits!  😊  Have a great Friday!
9:21 AM - 4 Sep 2009
 
Twitter
Khushbu Malik
‏@KhushbuMalik
Q: Why don’t ghosts like to go out in the rain?
A: Because it dampens their spirits!
5:31 AM - 16 Oct 2010