“It’s a/one hundred and hell degrees outside”  (or “It’s 100 and hell degrees outside”) means that it’s very hot.
   
“We know it’s 100-and-hell” was printed in the San Diego (CA) Union-Tribune on August 22, 2000. “Austin is 100 and hell degrees, but dry” was posted on Twitter by Marcus K. Dowling on March 18, 2009. “It gotta B Bout 100 and hell degrees outside” was posted on Twitter by Marcus Terry on May 13, 2009. “It is 100 and hell degrees outside” was posted on Twitter by Gena Webb on July 10, 2009.
     
“It’s going to be a hundred and hell degrees tomorrow!” was posted on Twitter by ✨ Laura 🍍 on July 13, 2009. “Its a hundred and hell degrees in phoenix 2day!” was posted on Twitter by Supa Dupa on August 1, 2009. “It’s a hundred and hell degrees outside!” was posted on Twitter by Stanley Johnson on June 23, 2010. “IT’S A HUNDRED AND HELL DEGREES TODAY!” was posted on Twitter by TamraCompletely on July 16, 2010.
   
“It’s gonna b One Hundred and Hell degrees today… I jus kno it!  SMH” was posted on Twitter by Stanley Johnson on May 4, 2010. “Sir, do you realize it’s one hundred and hell degrees outside?” was posted on Twitter by The Ordinary Beyoncé (Doc/Jefa/Queen) on May 7, 2010. “It feels like one hundred and hell degrees outside” was posted on Twitter by Gretta World Peace on June 13, 2010. “RT @ravey_babey IT IS ONE HUNDRED AND HELL DEGREES OUTSIDE!!!!!” was posted on Twitter  by Rei Hino on July 24, 2010.
   
“Summer is here. It’s a hundred and fuck you outside” is a related summer heat saying.
     
         
22 August 2000, San Diego (CA) Union-Tribune, “Human Pinwheels” Bodysurfing winner combined fortune, skill and daring” by Terry Rodgers, pg. D-2:
... the cool oceanfront breezes. “We know it’s 100-and-hell” ...
     
Twitter
Parand Darugar
@parand
Two hundred and hell degrees…
5:12 PM · Aug 18, 2007
 
Twitter
Marcus K. Dowling
@marcuskdowling
Work on vacation. I never sleep. My productivity level is ridiculous. Austin is 100 and hell degrees, but dry. Not on a DC level. Grand.
1:58 PM · Mar 18, 2009
   
Twitter
Marcus Terry
@Grustler_MT
man say! It gotta B Bout 100 and hell degrees outside… fenna swang ^ 2 Big T, cuz 1 thing 4sho this heat most def Brings the ladies out…
5:49 PM · May 13, 2009
   
Twitter
Gena Webb
@genawebb
It is 100 and hell degrees outside
5:33 PM · Jul 10, 2009
     
Twitter
✨ Laura 🍍 (ia 🦥)
@expat_laura
Tim (my DCSM): “It’s going to be a hundred and hell degrees tomorrow!” I love it. So true.
6:08 PM · Jul 13, 2009
 
Twitter
Diva (in Demand)
@DivaInDemand
It’s 100 and hell degrees outside!
6:26 PM · Jul 28, 2009
   
Twitter 
Supa Dupa
@XXXSupaDupa
Its a hundred and hell degrees in phoenix 2day!
6:35 PM · Aug 1, 2009
 
Twitter
G.☥
@prettygabrielle
its 91 degrees outside , but it feels more like 100 and hell!
4:06 PM · Aug 10, 2009
     
Twitter 
Forename Surname
@MikeyTheGreat
Lawd it’s hot outside! Feels like a hundred and hell degrees out here…
3:40 PM · Aug 21, 2009
   
Twitter
Stanley Johnson
@StanleyJMusic
It’s gonna b One Hundred and Hell degrees today… I jus kno it!  SMH
1:26 PM · May 4, 2010
   
Twitter
The Ordinary Beyoncé (Doc/Jefa/Queen)
@Sxy_NtheCity
I don’t know why my daddy chooses to talk dumbshit in the heat. Sir, do you realize it’s one hundred and hell degrees outside?
3:44 PM · May 7, 2010
 
Twitter
John André
@JayT843
I swear it was 100 and hell degrees in Atlanta today.
8:28 PM · May 15, 2010
     
Twitter
Gretta World Peace
@CakeByTheP0undX
It feels like one hundred and hell degrees outside.
6:41 PM · Jun 13, 2010
   
Twitter
Stanley Johnson
@StanleyJMusic
It’s a hundred and hell degrees outside!
12:14 PM · Jun 23, 2010
 
Twitter
key.
@SilenceIsFree
Its a 100 and hell degrees outside. The heat is so unnecessary
3:58 PM · Jul 6, 2010
     
Twitter
TamraCompletely
@thisistamra
IT’S A HUNDRED AND HELL DEGREES TODAY!
8:59 PM · Jul 16, 2010
   
Twitter
Rei Hino
@iEmbellish__
RT @ravey_babey IT IS ONE HUNDRED AND HELL DEGREES OUTSIDE!!!!!
3:44 PM · Jul 24, 2010
 
Twitter
Jermaine Brunson
@yeaiknow843
Man it’s 100 and HELL degrees outside!!!!
6:20 PM · Jul 19, 2011
   
Twitter
Theo Williams
@neauxera
It’s a hundred and hell degrees outside….
5:40 PM · Jul 22, 2011
 
October 2011, D (Dallas/Fort Worth, TX), “Better, Stronger, Colder” by Catherine Mallette, pg. 34:
And then, mercifully, it is over. Coach David leads me out, naked but toweled, into the alley behind the center to stand in the 100-and-hell-degree air. God, it feels good.
     
Twitter
Mel
@Mel711290
It’s a hundred and hell degrees outside. #OklahomaSummer
6:39 PM · Jun 27, 2012
   
Twitter
JC Chasez’s Thug Appeal
@_KimboNoSlice
It’s one hundred and hell degrees outside, bruh.
8:20 PM · Jul 11, 2014
   
Twitter
Amy Gowland
@AmyGowland
Penn on Las Vegas: “It is one hundred and hell degrees here.”
5:32 PM · Jun 28, 2015 from Winchester, NV
 
Twitter
Boog F. Merrill
@BoogF
Current temp in #Dallas 100 and hell degrees
7:14 PM · Aug 5, 2015
   
Twitter
DJ II You 💎
@King_7avage
It’s 100 and hell degrees outside 😩
6:56 PM · Jun 15, 2016 from Jefferson City, MO
 
Google Books
DEVEN:
The Seventh Star
By Arthur Grant
New York, NY: Page Publishing, Inc.
2017
Pg. ?:
It’s a hundred and hell degrees out here, dude,” pleads Jordy.
     
ESPN
Christopher Daniels: At the crossroads of immortality and oblivion
Mar 10, 2017
(...)
“I remember being in the Murphy Rec Center and it being 100 and hell degrees,” recalled Daniels, during an ESPN.com interview prior to ROH’s “Manhattan Mayhem” show at the Hammerstein Ballroom.
 
Twitter
-
@mayito1972
@KaitiBlake
it’s officially 100 and hell degrees in maverick county
6:56 PM · Jun 22, 2017
     
Twitter
BRANDY WOODEN
@BRANDEEEEEEEE
It is a hundred and hell degrees outside 🔥
6:04 PM · May 31, 2018
 
Twitter
Luxury Icy Doll ❄️🇫🇷
@kingRihh
It’s 100 and hell degrees outside wtf
2:00 PM · Jun 19, 2018
     
Twitter
Valerie Brown
@valerieinhoops
It’s a hundred and hell degrees today in Vegas ....
4:03 PM · Jul 12, 2020
   
Twitter
MG
@mariiamariiaG
It’s a hundred and hell naahh degrees outside wtf 😰
5:52 PM · Aug 18, 2020
   
Twitter
Sarah Night 🌑
@cernunnas
It’s one hundred and hell degrees outside.
3:43 PM · Aug 22, 2021
 
Twitter
Dontay Bishop
@Bishop_DST
Finally it’s not 100 and hell degrees out today
9:15 AM · Sep 2, 2021
     
Twitter
Petty Murphy
@gofthecooltable
It’s a hundred and hell degrees outside
5:40 PM · May 7, 2022
 
Twitter
Jolly Ole Saint Richard 😈 🏳️‍🌈
@fokised1
Replying to @Yep_itsKeice
Whew. Phoenix. Where it’s 100 and hell degrees from February to November every year lol.
12:26 PM · Jun 13, 2022
 
Twitter
LaToYAH 👸🏾💕
@ToiWeezy
“It’s a 100 and hell no degrees” 💀
1:47 PM · Jun 13, 2022
   
Twitter 
𝖕𝖗𝖎𝖓𝖈𝖊𝖘𝖘 𝖏𝖔𝖗𝖉𝖞 👑
@flubaphone
bitch it is one hundred and hell degrees outside right now i’m about to LOSE IT
5:39 PM · Jul 15, 2022
 
Twitter
Fighting Chance Network
@USApe_12741
Dont worry about us in Texas. It’s only 100 and hell degrees outside.
7:24 PM · Jul 18, 2022