Il fait un froid de canard.
It's really cold!

Ça caille.
It's cold. (It's so cold your blood coagulates.)

Je me caille les miches.
My buttocks are freezing.

Je suis chaud does not mean that "you feel hot temperature wise". Depending on the contexts it's a declaration that you are either hot/sexy or expression meaning that you are partant pour un projet (enthusiastic for a project).

-Tu veux aller à la plage avec moi ?
Do you want to go the beach with me?
-Je suis chaud.
Yes, I'm enthusiastic.

-Tu veux aller au pôle nord avec moi ?
Do you want to go to the north pole with me?
-Non, je suis pas très chaud là.
I'm not that enthusiastic about that proposition.

Elle est chaude comme la braise.
She's hot like embers.

Pleuvoir comme des vaches qui pissent.
Litterally it's raining like pissing cows. (It's raining really hard.)

Il pleut des hallebardes.
Litterally it's raining halberds. (It's raining really hard.)

Il pleut des cordes.
Litterally it's raining ropes. (It's raining really hard.)

C'est un vrai déluge.
Literally it's a flood. (It's really raining hard.)

Tu vas être saucée si tu pars maintenant.
You're going to be turned into sauce if you leave now. (because you'd be so wet)