Yo momma so dumb, when your dad said it was chilly outside, she ran outside with a spoon.
Chilly Spoon
Explanation
Explain Bear
Alright listen up, dummy! This "yo momma" joke is all about how dumb your momma is. The joke is that when your dad said it was chilly, your momma grabbed a spoon. Get it? You eat chili with a spoon, not chilliness. It's funny because grabbing a spoon to deal with being cold makes absolutely no sense! I bet you are eating your chili with a fork now.