“Wiener Wednesday” (also often spelled as “Weiner Wednesday”) is a day when hot dogs (“wieners”) are sold by an establishment, often at a reduced price. “Wiener Wednesday” has been cited in print since at least 1994 and “Weiner Wednesday” since at least 2001).
   
Other slang names for days of the week include Shunday, Sober Sunday, Margarita Monday, Messed-up Monday, Mojito Monday, Moonshine Monday, Boozeday Tuesday, Taco Tuesday, Tanked Tuesday, Tasty Tuesday, Tequila Tuesday, Tipsy Tuesday, Trashed Tuesday, Twisted Tuesday, Wasted Wednesday, Whiskey Wednesday, Wine Wednesday, Winesday Wednesday, Wing Wednesday, Thirsday, Thirstday, Thirsty Thursday, Fajita Friday, Fucked-up Friday, Shit-faced Saturday, Sloppy Saturday, Sloshed Saturday and Smashed Saturday
   
 
15 June 1994, The Post and Courier (Charleston, SC), pg. 7-A, col. 4 ad:
Enjoy free food from Security Pacific and WEZL FM—broadcasting love from 10 a.m. to noon, followed by Weazel Wiener Wednesday until 1 p.m.
(Security Pacific Financial Services.—ed.)
 
13 July 1995, The Post and Courier (Charleston, SC), “Red Cross makes appeal for blood, This Week in Moncks Corner sec., pg. 5, col. 3:
July 26, noon- 3 p.m. at Piggly Wiggly in Quadrangle Shopping Center. WEZL 103.5-FM Radio will be at this blood drive for their weekly Wiener Wednesday. Donors can eat a free lunch, then give blood.
 
10 August 1999, Standard (St. Cathatrines, ON), “New York-Penn League Stompers cut down,” pg. C3:
Wednesday will be Wiener Wednesday with $1 hot dogs. In addition, a pair of tickets to the upcoming world rowing championships will be given away.
       
16 May 2000, The Independent Record (Helena, MT), pg. 1B, col. 1:
Wednesdays “Wiener Wednesday” by KBLL Cloverdale and Snyder Bakery (50-cent hot dogs all night)
 
5 April 2001, The Tennessean (Nashville, TN), “Nashville Sounds” (minor league baseball club), pg. 6C, col. 2:
Weiner Wednesdays
25c hot dogs
 
Twitter
Jill-Leslie
@KSJILL
Dutch said to me: oh, j. that’s not what “wiener wednesday” at the ballpark means. we seriously need to get you a date.
11:46 AM - 9 Jul 2008
 
Twitter 
Chriselda
@Chriselda
If its taco tuesday .... Can it now be weiner wednesday? I am in the mood for some schnitz
11:07 AM - 29 Oct 2008
   
Google Books
Food Lovers’ Guide to® Atlanta:
The Best Restaurants, Markets & Local Culinary Offerings
By Malika Harricharan
Guilford, CT: Globe Pequot Press
2012
Pg. 103:
The restaurant also has a line of “haute” dogs that are available each day, and on Wednesday (dubbed Wiener Wednesday) they are available for only $2.
 
Twitter 
Double Dip Depot
@DoubleDipDepot
Happy Weiner Wednesday! $1.00 off all dogs all day long
9:11 AM - 25 Jul 2018
 
Twitter
The Pop Shop
@popshopusa
Every Wednesday is WIener Wednesday! Our Pop Dog Platter is just $3.99, all other dog platters are $1 off.
11:00 AM - 25 Jul 2018