Coffee is usually—but not always—served hot. A winter joke is:
 
“It was so cold that Dunkin’ Donuts (or Starbucks or a local coffeehouse) was serving coffee on a stick.”
 
“It’s so cold, street vendors are selling coffee on a stick” was printed in many newspapers in January 1988. “It was so cold…Starbucks was serving coffee on a stick!” was printed in a 2003 blog. “It’s so cold, dunkin donuts is servin coffee on a stick” was posted on Twitter on December 8, 2010.
 
The joke is somewhat dated. “Coffee on a stick” is a product that is sold when it’s hot.
 
     
Wikipedia: Dunkin’ Donuts
Dunkin’ Donuts is an American global donut company and coffeehouse based in Canton, Massachusetts, in Greater Boston. It was founded in 1950 by William Rosenberg in Quincy, Massachusetts. Since its founding, the company has grown to become one of the largest coffee and baked goods chains in the world, with more than 12,000 restaurants in 36 countries. The chain’s products include donuts, bagels, other baked goods, and a wide variety of hot and iced beverages.
 
Wikipedia: Starbucks
Starbucks Corporation is an American coffee company and coffeehouse chain. Starbucks was founded in Seattle, Washington in 1971. As of November 2016, it operates 23,768 locations worldwide.
     
7 March 1982, Southern Illinoisan (Carbondale, IL), “Garfield” comic strip by Jim Davis, comics, sec., pg. ?:
MAN: THERE’S NOTHING LIKE CAMPING OUT IN COLD WEATHER. (...) WE HAVE EVERYTHING…OUR FIRE, OUR SHELTER…
CARFIELD (the cat, noticing coffee stuck to the spoon): OUR COFFEE ON A STICK.
 
6 January 1988, Wausau (WI) Daily Herald, “So, how cold is it? It’s so cold that…” by by Andy Smith (Gannett News Service,) pg. 1, col. 1:
OK, just how cold is it?
 
Well…it’s so cold the Jolly Green Giant turned blue.
 
It’s so cold, we saw a dog stuck to a fire hydrant.
 
It’s so cold, street vendors are selling coffee on a stick.
     
Athropolis (December 4, 2003)
It was so cold…
(...)
13, It was so cold . . .
Starbucks was serving coffee on a stick!
 
7 November 2007, Daily Record (Morristown, NJ), “From the editor: We hate raking leaves,” This Week sec., pg. 1, col. 5:
Those of you who remember former “Tonight Show” host Johnny Carson know that a favorite joke always began: “Man, it was cold in Hollywood today ...” and then a pause so someone in the audience could yell: “How cold was it?”
 
“It was so cold,” Carson would answer, “that pickpockets were sticking their hands in strangers’ pockets just to keep their hands warm!” Or “... that Starbucks was serving coffee on a stick.”
     
27 January 2008, Star-News (Wilmington, NC), “Warm up with antiques or opera,” pg. ?::
It looks like this is the time to start breaking out all those “it was so cold” jokes that help all of us to get through these times when even the bright coastal sunshine fails to generate much warmth.
 
Okay, I’m game. See if you can crack a smile over these: It was so cold that
(...)
. . . Port City Java was serving coffee on a stick!
     
Google News Archive
6 February 2008, Phillips County News (Malta, MT), “On the Street: Is it just me…or is it COLD?” with John Degel, pg. 2, col. 1:
How cold was it?
 
It was so cold…
(...)
Crossroad Coffee was serving coffee on a stick!
 
Twitter
Bo‏
@twitterbo
It is so cold up North . . .Starbucks is serving coffee on a stick! ....😊
8:05 AM - 17 Dec 2008
 
Twitter
lynn‏
@lynngg
RT @DaveLetterman: It’s going to be so cold tonight at Times Square that Starbucks will be serving coffee-on-a-stick. Your turn…
2:24 PM - 31 Dec 2008
 
Twitter
TweetyWords‏
@TweetyWords
RT @DavidLetterman It’s going to be so cold tonight at Times Square that Starbucks will be serving coffee-on-a-stick. Your turn
6:37 PM - 1 Jan 2009
       
Twitter
Heidi 💖 💚 💜‏
@NewKids4Vegas
Replying to @DonnieWahlberg
@DonnieWahlberg it’s so cold, dunkin donuts is servin coffee on a stick!
12:51 PM - 8 Dec 2010
 
30 June 2014, The Advertiser (Adelaide, Australia), “How to beat the chill and survive ‘til spring” by Ali Clarke, pg. 13:
Cold? How cold! It’s so cold Cibo is serving coffee on a stick and the local flasher has been caught describing himself to the ladies.
 
1420 WBSM (New Bedford, MA)
THE BEST ‘IT’S SO COLD…’ JOKES 2016
KASEY SILVIA February 10, 2016
(...)
Dunkin’ Donuts is serving coffee on a stick.
 
Twitter
Chris P. Bacon‏
@ChrisPBaconJr
Dad says, it was so cold, Starbuck’s drive-through was serving coffee-on-a-stick. Free for $3 dollars each.  #MarchDadness
7:20 PM - 15 Mar 2017
 
Twitter
Asbel‏
@asbel89
It was so cold Starbucks was serving coffee on a stick!
6:49 AM - 5 Jan 2018 from Camden, NJ