Start with "It's so hot outside" then add something that's happened! 

Remember to keep it HP-appropriate. 

It's so hot outside all of the vehicles' tyres have stuck to the roads!

its so hot outside my car ac won't keep up

It's so hot outside the pool started to boil

its so hot outside my tires melted

It's so hot outside my shoes melted to the pavement.

It's so hot outside I'm sitting in the dog's kiddy pool. 

It's so hot I melted

it's so hot the chickens are deflated

It's so hot outside the leaves fell off the trees