“Triple H” weather is hazy, hot and humid. “It’s one of those Triple H (Hazy, Hot and Humid) mornings that we’ve been having lately” was printed in the New York (NY) Times on July 22, 1984.
   
             
22 July 1984, New York (NY) Times, “For Some, Mail-Order Catalogues Are a Course in Required Reading” by Rita Licciardolo, New Jersey sec., pg. 20, col. 3:
IT’S ONE of those Triple H (Hazy, Hot and Humid) mornings that we’ve been having lately.
     
19 May 1987, Durham (NC) Sun, “Durham Aquatic Club makes a big splash” by Elson Armstrong, pg. 5-B, col. 1:
With Triple-H weather (hot, humid, hazy) becoming a part of the Durham scene for the next four months or so, and with Duke swimming coach Bob Thompson spending much of his working day around the pool, you would think Thompson has the coolest job in town.
 
3 June 1987, Morning Call (Allentown, PA), “Thunderstorm Brings Relief from Heat,” pg. B3:
A string of “triple H” days (hazy, hot and humid) ended yesterday as daily high temperatures dropped from the 90s into the 80s.
     
Google Books
North Country Farm News
1987
Pg. 32:
TRIPLE H DAYS Hazy, hot and humid!
 
10 July 1989, Democrat and Chronicle (Rochester, NY), pg. 8A, col. 1:
WEATHER STATION
DAYTON, Ohio—The triple ‘h’ deal—hot, humid and hazy,” said Jeff Czajka yesterday.
     
26 August 1993, Daily Press (Newport News, VA), “Triple H’s Hover: Hazy, Hot, Humid” by Matt Murray, pg. C1:
That large outdoor broiler known as the Peninsula got turned up a few degrees Wednesday, and things are expected to keep cooking for a few more days.
   
Google Books
Irresistible Stranger
By Linda Cajio
New York, NY: Random House Publishing Group
1994
Pg. 119:
England was much cooler in the summer than Pennsylvania’s triple-H version: hot, hazy, and humid.
   
Google Books
Taking on Heart Disease:
Famous Personalities Recall how They Triumphed Over the Nation’s #1 Killer and how You Can Too
By Larry King
New York, NY: Random House
2004
Pg. 98:
It was one of Washington D.C.‘s “triple-H” days — hazy, hot, and humid.
 
Twitter
Justin
@xxdesmus
Triple H’s today (hazy, hot, and humid) ...avoiding the heat like the plague.
3:53 PM - 8 Jul 2007
     
WRAL.com (Raleigh, NC)
‘Triple H’ weather is here to stay
Posted June 4, 2008
RALEIGH, N.C. — Wednesday marked the beginning of a very hot period that will likely last through the next week, WRAL Chief Meteorologist Greg Fishel said.
(...)
That chance is only slight, however, and should be over by about 10 p.m., according to the National Weather Service. In most areas of the Triangle, Wednesday night will be muggy and warm – the three summertime Hs of hot, humid and hazy.
 
Twitter
Natick Weather
@NatickWeather
Signals continue to point towards a very hot (and potentially record breaking) weekend coming up away from the coast across Southern New England…get ready for the “Triple H’s” (Hazy, Hot & Humid)! GFS pictured:
11:49 AM - 24 Jun 2018
 
Twitter
Steven Adam
@StevenA54
Replying to @ABC7EileenW
Good morning! I work the weekends but welcome the triple H. Hot, Hazy and Humid! Cool drinks and a dip at the pool!
7:45 AM - 28 Jun 2018 from Annandale, VA